Description of problem:
* if the fcontext pattern is defined in policy then adding the same pattern should always result in an error message
* if the fcontext pattern is defined in policy and cannot be deleted then every attempt to remove such fcontext pattern should result in an error message

Version-Release number of selected component (if applicable):
policycoreutils-python-2.0.83-30.1.el6_8.x86_64
policycoreutils-2.0.83-30.1.el6_8.x86_64

How reproducible:
* always

Steps to Reproduce:
# semanage fcontext -l | grep /var/log/httpd
/var/log/httpd(/.*)?                               all files          system_u:object_r:httpd_log_t:s0 
# semanage fcontext -a -t httpd_log_t '/var/log/httpd(/.*)?'
libsemanage.dbase_llist_query: could not query record value (No such file or directory).
# semanage fcontext -a -t httpd_log_t '/var/log/httpd(/.*)?'
# semanage fcontext -a -t httpd_log_t '/var/log/httpd(/.*)?'
# semanage fcontext -l | grep /var/log/httpd
/var/log/httpd(/.*)?                               all files          system_u:object_r:httpd_log_t:s0 
# semanage fcontext -d -t httpd_log_t '/var/log/httpd(/.*)?'
# semanage fcontext -d -t httpd_log_t '/var/log/httpd(/.*)?'
/usr/sbin/semanage: File context for /var/log/httpd(/.*)? is defined in policy, cannot be deleted
# semanage fcontext -d -t httpd_log_t '/var/log/httpd(/.*)?'
/usr/sbin/semanage: File context for /var/log/httpd(/.*)? is defined in policy, cannot be deleted
#