[lldb] Remove extra space in step logging message

When seeing the extra space in the log, it wasn't clear if there was a missing
printf argument. Removing the extra space removes the potential confusion.

Author: kastiglione

lldb/source/Target/Thread.cpp

@@ -989,7 +989,7 @@ Vote Thread::ShouldReportStop(Event *event_ptr) {
     // the last plan, regardless of whether it is private or not.
     LLDB_LOGF(log,
               "Thread::ShouldReportStop() tid = 0x%4.4" PRIx64
-              ": returning vote  for complete stack's back plan",
+              ": returning vote for complete stack's back plan",
               GetID());
     return GetPlans().GetCompletedPlan(false)->ShouldReportStop(event_ptr);
   } else {