Fix looping in mxssmp

This change corrects a problem in StatsGlobals::checkForDeadProcesses
which causes looping in the mxssmp process while it holds the
share segment semaphore, which leads to hanging of call SQL processes
on the node.

Change-Id: Id5477e516cf0b1519f7e892bad2cf3ff84f79e34
Closes-Bug: #1368891
Merge "Fix looping in mxssmp"