Revert "Ignore heartbeats lock fails"
Revert "Ignore heartbeats lock fails"

It seems that there are at least two level of ruby-stomp brokenness and
the fact that the mutex in original commit is locked actually means
there is no heartbeat received in time and we need to do something about
this.

This reverts commit 8318d7056556337f17f596edad9d7eed48ec3ca5.

Partial-Bug: #1644618
Change-Id: I565f430d17bcee2c50c0ddc8ecc11f3dc8b420ed
(cherry picked from commit 13b4d0f38e2a3e1c4d0ac0d91a7bce1dc23d7c8a)

stackforge/fuel-library,stackforge/fuel-library,stackforge/fuel-library,stackforge/fuel-library