webadmin: Fix import cluster fingerprint validation issues

Fingerprint will not be validated if either host address
or password is empty.

Change-Id: I63878f1430f80d672b2aec35685187a74c921b17
Bug-Url: https://bugzilla.redhat.com/887830
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>