core: avoid loading GIO modules

Turns out the dconf modules is leaky and breaks the valgrind run. In any case,
it's not a good idea to load the modules for the daemon, it just takes time
and memory.

On a Fedora/x86_64 desktop it adds up to 5M to the RSS.

include/nm-test-utils.h

@@ -439,6 +439,11 @@ __nmtst_init (int *argc, char ***argv, gboolean assert_logging, const char *log_
 	/* ensure that monotonic timestamp is called (because it initially logs a line) */
 	nm_utils_get_monotonic_timestamp_s ();
 #endif
+
+	/* Avoid loading the VFS modules we don't use in the daemon.
+	 * See: src/main-utils.c:nm_main_utils_early_setup() */
+	setenv ("GIO_USE_VFS", "local", 1);
+	setenv ("GIO_MODULE_DIR", "", 1);
 }
 
 #ifdef __NETWORKMANAGER_LOGGING_H__

src/main-utils.c

@@ -205,6 +205,9 @@ nm_main_utils_early_setup (const char *progname,
 	 * talking on the session bus.  See rh #588745
 	 */
 	setenv ("GIO_USE_VFS", "local", 1);
+	/* Don't load GIO modules. We just want to load plain files and the
+	 * modules would just take extra memory. */
+	setenv ("GIO_MODULE_DIR", "", 1);
 
 	/*
 	 * Set the umask to 0022, which results in 0666 & ~0022 = 0644.