scripted-diff: Small locking rename

Call sync.h primitives "locks" and "mutexes" instead of "blocks" and "waitable
critical sections" to match current coding conventions and c++11 standard
names.

This PR does not rename the "CCriticalSection" class (though this could be done
as a followup) because it is used everywhere and would swamp the other changes
in this PR. Plain mutexes should mostly be preferred instead of recursive
mutexes in new code anyway.

-BEGIN VERIFY SCRIPT-
set -x
set -e
ren() { git grep -l $1 | xargs sed -i s/$1/$2/; }
ren CCriticalBlock           UniqueLock
ren CWaitableCriticalSection Mutex
ren CConditionVariable       std::condition_variable
ren cs_GenesisWait           g_genesis_wait_mutex
ren condvar_GenesisWait      g_genesis_wait_cv
perl -0777 -pi -e 's/.*typedef.*condition_variable.*\n\n?//g' src/sync.h
-END VERIFY SCRIPT-

src/httpserver.cpp

@@ -69,7 +69,7 @@ class WorkQueue
 {
 private:
     /** Mutex protects entire object */
-    CWaitableCriticalSection cs;
+    Mutex cs;
     std::condition_variable cond;
     std::deque<std::unique_ptr<WorkItem>> queue;
     bool running;