Description of problem:
When a floating IP is disassociated, the following error can be seen in l3-agent.log:

ERROR neutron.agent.linux.interface [-] Failed deleting ingress connection state of floatingip 172.16.51.202
TRACE neutron.agent.linux.interface Traceback (most recent call last):
TRACE neutron.agent.linux.interface   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/interface.py", line 129, in delete_conntrack_state
TRACE neutron.agent.linux.interface     extra_ok_codes=[1])
TRACE neutron.agent.linux.interface   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/ip_lib.py", line 468, in execute
TRACE neutron.agent.linux.interface     check_exit_code=check_exit_code, extra_ok_codes=extra_ok_codes)
TRACE neutron.agent.linux.interface   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py", line 83, in execute
TRACE neutron.agent.linux.interface     raise RuntimeError(m)
TRACE neutron.agent.linux.interface RuntimeError: 
TRACE neutron.agent.linux.interface Command: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ip', 'netns', 'exec', 'qrouter-0ec4cf3a-b87e-4db6-8dfc-12df9aef7580', 'conntrack', '-D', '-d', '172.16.51.202']
TRACE neutron.agent.linux.interface Exit code: 96
TRACE neutron.agent.linux.interface Stdout: ''
TRACE neutron.agent.linux.interface Stderr: '/usr/bin/neutron-rootwrap: Executable not found: conntrack (filter match = conntrack)\n'
TRACE neutron.agent.linux.interface 
ERROR neutron.agent.linux.interface [-] Failed deleting egress connection state of floatingip 172.16.51.202
TRACE neutron.agent.linux.interface Traceback (most recent call last):
TRACE neutron.agent.linux.interface   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/interface.py", line 139, in delete_conntrack_state
TRACE neutron.agent.linux.interface     extra_ok_codes=[1])
TRACE neutron.agent.linux.interface   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/ip_lib.py", line 468, in execute
TRACE neutron.agent.linux.interface     check_exit_code=check_exit_code, extra_ok_codes=extra_ok_codes)
TRACE neutron.agent.linux.interface   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py", line 83, in execute
TRACE neutron.agent.linux.interface     raise RuntimeError(m)
TRACE neutron.agent.linux.interface RuntimeError: 
TRACE neutron.agent.linux.interface Command: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf', 'ip', 'netns', 'exec', 'qrouter-0ec4cf3a-b87e-4db6-8dfc-12df9aef7580', 'conntrack', '-D', '-q', '172.16.51.202']
TRACE neutron.agent.linux.interface Exit code: 96
TRACE neutron.agent.linux.interface Stdout: ''
TRACE neutron.agent.linux.interface Stderr: '/usr/bin/neutron-rootwrap: Executable not found: conntrack (filter match = conntrack)\n'
TRACE neutron.agent.linux.interface 


This is an all-in-one installation, ml2 plugin for neutron, on RHEL 7.

The dependency to conntrack seems to have been introduced as backport between 2014.1.2 and 2014.1.3.

Version-Release number of selected component (if applicable):
python-neutronclient-2.3.4-3.el7ost.noarch
openstack-neutron-2014.1.3-5.el7ost.noarch
python-neutron-2014.1.3-5.el7ost.noarch
openstack-neutron-openvswitch-2014.1.3-5.el7ost.noarch
openstack-neutron-ml2-2014.1.3-5.el7ost.noarch



Snippet from packstack configuration:
[...]
CONFIG_NEUTRON_L2_PLUGIN=ml2
CONFIG_LBAAS_INSTALL=n
CONFIG_NEUTRON_METERING_AGENT_INSTALL=n
CONFIG_NEUTRON_FWAAS=y
CONFIG_NEUTRON_ML2_TYPE_DRIVERS=vxlan
CONFIG_NEUTRON_ML2_TENANT_NETWORK_TYPES=vxlan
CONFIG_NEUTRON_ML2_MECHANISM_DRIVERS=openvswitch
CONFIG_NEUTRON_ML2_FLAT_NETWORKS=*
CONFIG_NEUTRON_ML2_VLAN_RANGES=
CONFIG_NEUTRON_ML2_TUNNEL_ID_RANGES=
CONFIG_NEUTRON_ML2_VXLAN_GROUP=
CONFIG_NEUTRON_ML2_VNI_RANGES=10:100
CONFIG_NEUTRON_L2_AGENT=openvswitch
CONFIG_NEUTRON_LB_TENANT_NETWORK_TYPE=local
CONFIG_NEUTRON_LB_VLAN_RANGES=
CONFIG_NEUTRON_LB_INTERFACE_MAPPINGS=
CONFIG_NEUTRON_OVS_TENANT_NETWORK_TYPE=gre
CONFIG_NEUTRON_OVS_VLAN_RANGES=phynet1:1:4094
CONFIG_NEUTRON_OVS_BRIDGE_MAPPINGS=
CONFIG_NEUTRON_OVS_BRIDGE_IFACES=

CONFIG_NEUTRON_USE_NAMESPACES=y