tree-wide: use coccinelle to patch a lot of code to use mfree()

This replaces this:

        free(p);
        p = NULL;

by this:

        p = mfree(p);

Change generated using coccinelle. Semantic patch is added to the
sources.

src/basic/bitmap.c

@@ -145,8 +145,7 @@ bool bitmap_isclear(Bitmap *b) {
 void bitmap_clear(Bitmap *b) {
         assert(b);
 
-        free(b->bitmaps);
-        b->bitmaps = NULL;
+        b->bitmaps = mfree(b->bitmaps);
         b->n_bitmaps = 0;
         b->bitmaps_allocated = 0;
 }