Fixing backendHostResourceTests expectation results

After adding http://gerrit.ovirt.org/17194 that fixes the host mapping
in update() function, the tests were needed to be modify to expect for
the set value.
Checking for rootPassword, should be the rootPassword that set for the
action.

Change-Id: I00c710edac936f9d850740199824bd28a295fc87
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>