config: Don't crash if we don't have a config file

Adding a check in weston_config_full_path so that
we don't crash if we started without a config file.

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>

shared/config-parser.c

@@ -385,7 +385,7 @@ weston_config_parse(const char *name)
 const char *
 weston_config_get_full_path(struct weston_config *config)
 {
-	return config->path;
+	return config == NULL ? NULL : config->path;
 }
 
 int

src/compositor.c

@@ -3492,8 +3492,12 @@ int main(int argc, char *argv[])
 	}
 
 	config = weston_config_parse("weston.ini");
-	weston_log("Using config file '%s'\n",
-		   weston_config_get_full_path(config));
+	if (config != NULL) {
+		weston_log("Using config file '%s'\n",
+			   weston_config_get_full_path(config));
+	} else {
+		weston_log("Starting with no config file.\n");
+	}
 	section = weston_config_get_section(config, "core", NULL, NULL);
 	weston_config_section_get_string(section, "modules", &modules, "");