Description of problem:
Failed to save password with ticking 'Save this password in your keyring' using virt-manager for root user.

Version-Release number of selected component (if applicable):
virt-manager-1.4.0-2.el7.noarch
libvirt-2.0.0-10.el7.x86_64
pygobject3-3.14.0-3.el7.x86_64

How reproducible:
100%

Steps to Reproduce:

1. Prepare a vnc or spice guest with password set.
eg:
# virsh dumpxml rhel6.8-spice --security-info |grep passwd
    <graphics type='spice' port='5900' autoport='yes' listen='127.0.0.1' passwd='aaaaaa'>
2. Launch virt-manager
# virt-manager
3. Open the guest and type correct password, make sure you can login successfully.
4. Close the guest window and open the guest again, type correct password and with checking on 'Save this password in your keyring', then click login button, login successfully.
5. Close the guest window, and open the guest again, check password is remembered or not and also check "Save this password in your keyring" is ticked or not.


Actual results:
Password is not remembered and "Save this password in your keyring" is not ticked.

Expected results:
Password is remembered and "Save this password in your keyring" is ticked.

Additional info:
1. virt-manager debug info:

[Fri, 23 Sep 2016 02:20:32 virt-manager 14217] DEBUG (keyring:59) Using keyring session /org/freedesktop/secrets/session/s2
[Fri, 23 Sep 2016 02:20:39 virt-manager 14217] ERROR (keyring:87) Failed to add keyring secret
Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/keyring.py", line 84, in add_secret
    props, params, replace)[0]
  File "/usr/lib64/python2.7/site-packages/gi/overrides/Gio.py", line 171, in __call__
    None)
Error: g-io-error-quark: GDBus.Error:org.freedesktop.Secret.Error.NoSuchObject: The '/org/freedesktop/secrets/aliases/default' object does not exist (36)

2. It works with non-root user.
$ virt-manager -c qemu:///system