gvfs: disable the built-in FSMonitor

When using a virtual file system layer, the FSMonitor does not make
sense.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

fsmonitor-ipc.c

@@ -10,6 +10,8 @@
 
 int fsmonitor_ipc__is_supported(void)
 {
+	if (git_config_get_virtualfilesystem())
+		return 0;
 	return 1;
 }