[INTERNAL] fixed JID search

The resource hint was not used when searching for JIDs.

While this does not work an almost any XMPP server it worked on our
ejabberd server and so the STF tests were producing errors as an extra
dialog was shown that is not handled by the test framework.

Change-Id: Ie844b7224bbdb1c677c32c0de3cc120351215f7a
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1503
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>