Avoiding legacy health servlet usage

Avoidind legacy health servlet usage to check engine health in favor
of REST API.

Change-Id: I48225db31b57f70687887f4c06fb923648bfe9f6
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1026723
Signed-off-by: Simone Tiraboschi <stirabos@redhat.com>