Replace free and return NULL with return mfree

src/shared/condition.c

@@ -78,8 +78,7 @@ Condition* condition_new(ConditionType type, const char *parameter, bool trigger
 
         r = free_and_strdup(&c->parameter, parameter);
         if (r < 0) {
-                free(c);
-                return NULL;
+                return mfree(c);
         }
 
         return c;

src/shared/dissect-image.c

@@ -648,8 +648,7 @@ DissectedImage* dissected_image_unref(DissectedImage *m) {
         strv_free(m->machine_info);
         strv_free(m->os_release);
 
-        free(m);
-        return NULL;
+        return mfree(m);
 }
 
 static int is_loop_device(const char *path) {

src/shared/loop-util.c

@@ -152,9 +152,7 @@ LoopDevice* loop_device_unref(LoopDevice *d) {
         }
 
         free(d->node);
-        free(d);
-
-        return NULL;
+        return mfree(d);
 }
 
 void loop_device_relinquish(LoopDevice *d) {