removed no-op code in mem::~Mem()

This also stopped a an error from ocurreing in the thread-chinking version because when global destructors are run then parts of pthreads no longer works

Mem.cpp

@@ -234,7 +234,6 @@ Mem::Mem() {
 }
 
 Mem::~Mem() {
-	if ( getUsedMem() == 0 ) return;
 }