btrfs-progs: Replace usage of list_for_each with list_for_each_entry

btrfs-progs: Replace usage of list_for_each with list_for_each_entry

There are a couple of places where instead of the more succinct
list_for_each_entry the code uses list_for_each. This results in
slightly more code with no additional benefit as well as no
coherent pattern. This patch makes the code uniform. No functional
changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
[ remove unused variable in uuid_search ]
Signed-off-by: David Sterba <dsterba@suse.com>