wgl: Fix an extra break statement.

This would have leaked our TLS indices on process exit.

Fixes #32

src/dispatch_wgl.c

@@ -130,7 +130,6 @@ DllMain(HINSTANCE dll, DWORD reason, LPVOID reserved)
 
         data = TlsGetValue(wgl_tls_index);
         LocalFree(data);
-        break;
 
         if (reason == DLL_PROCESS_DETACH) {
             TlsFree(gl_tls_index);