Properly implement DllCanUnload ref counting.

dlls/dmscript/scripttrack.c

diff --git a/dlls/dmscript/scripttrack.c b/dlls/dmscript/scripttrack.c
index b489a69..25af7eb 100644
--- a/dlls/dmscript/scripttrack.c
+++ b/dlls/dmscript/scripttrack.c
@@ -55,6 +55,8 @@
 
 	TRACE("(%p): AddRef from %ld\n", This, ref - 1);
 
+	DMSCRIPT_LockModule();
+
 	return ref;
 }
 
@@ -67,6 +69,9 @@
 	if (ref == 0) {
 		HeapFree(GetProcessHeap(), 0, This);
 	}
+
+	DMSCRIPT_UnlockModule();
+
 	return ref;
 }