core: Remove XmlRpcUtilsTest

Removed XmlRpcUtilsTest, as it had no usable code anyway - it was a
component test, not a unit test, and was all commented out anyway.

Change-Id: I59c21980fecdfed3bf6e98b1cbbbd3d483032512
Signed-off-by: Allon Mureinik <amureini@redhat.com>