Fixed code to not allow deletion of locked domains.

Added spec test to verify fixed code.

https://bugzilla.redhat.com/show_bug.cgi?id=1173712
https://bugzilla.redhat.com/show_bug.cgi?id=1176202
Fixed 4 occurrences of "can not" to "cannot".

https://bugzilla.redhat.com/show_bug.cgi?id=1173712
https://bugzilla.redhat.com/show_bug.cgi?id=1176202
Merge pull request #1263 from h-kataria/automate_domain_delete_fix

Fixed code to not allow deletion of locked domains.