Remove MEMLEAKFINDER_NOT_A_LEAK from FileStream

It's not clear why we need to tell the memory leak tracking system to ignore
FileStream objects if they raise an exception in their constructors. The
objects should still be destroyed normally. Additionally, now that we
allocate more of them on the heap (for NamedLock), this can cause later
allocations to be silently ignored as not-leaks, which is causing
test_memory_leak_detection to fail.

lib/common/FileStream.cpp

@@ -120,8 +120,6 @@ void FileStream::OpenFile(int flags, int mode, lock_mode_t lock_mode)
 
 	if(mOSFileHandle == INVALID_FILE)
 	{
-		MEMLEAKFINDER_NOT_A_LEAK(this);
-
 		// Failed to open the file. What's the reason? The errno which indicates a lock
 		// conflict depends on the locking method.
 
@@ -225,7 +223,6 @@ FileStream::FileStream(tOSFileHandle FileDescriptor)
 {
 	if(mOSFileHandle == INVALID_FILE)
 	{
-		MEMLEAKFINDER_NOT_A_LEAK(this);
 		BOX_ERROR("FileStream: called with invalid file handle");
 		THROW_EXCEPTION(CommonException, OSFileOpenError)
 	}
@@ -250,7 +247,6 @@ FileStream::FileStream(const FileStream &rToCopy)
 	if(mOSFileHandle < 0)
 #endif
 	{
-		MEMLEAKFINDER_NOT_A_LEAK(this);
 		BOX_ERROR("FileStream: copying unopened file");
 		THROW_EXCEPTION(CommonException, OSFileOpenError)
 	}