Provide more generic string in testAssert of some TCs

CLI test case were failing on RHEL systems as the error string
on Fedora19 and RHEL6.4 systems are different however a more gereric
string is there on both of the systems and this is about that only.
It replaces the 'ECONNREFUSED' & 'No address associated with hostname'
with 'Check that the admin_url is valid'.Now the TCs pass on both of
the OS.

Change-Id: I3ba0f169dddf29368f0adb74027256dcdc894b89
Signed-off-by: Pushpesh Sharma <psharma@redhat.com>
Reviewed-on: http://review.gluster.org/6719
Reviewed-by: Luis Pabon <lpabon@redhat.com>
Tested-by: Luis Pabon <lpabon@redhat.com>