support: Fix memory leaks in FUSE tests

The internal read buffer (used by all FUSE tests) was not freed.
The support/tst-support_fuse test missed a deallocation.

support/support_fuse.c

@@ -659,6 +659,7 @@ support_fuse_unmount (struct support_fuse *f)
   if (rmdir (f->mountpoint) != 0)
     FAIL ("FUSE: rmdir (\"%s\"): %m", f->mountpoint);
   xclose (f->fd);
+  free (f->buffer_start);
   free (f->mountpoint);
   free (f->readdir_buffer);
   free (f);

support/tst-support_fuse.c

@@ -331,6 +331,7 @@ do_test (void)
   {
     char *subdir_path = xasprintf ("%s/subdir", support_fuse_mountpoint (f));
     xmkdir (subdir_path, 01234);
+    free (subdir_path);
   }
 
   {