btrfs: use PTR_ERR_OR_ZERO
btrfs: use PTR_ERR_OR_ZERO

replace IS_ERR/PTR_ERR

Cc: Chris Mason <e2e8c5702d8ed5f565988a1cf5bb35c9ce199e5e@fb.com>
Cc: Josef Bacik <631dfb3d07694fdcf26abc7aac2c6c2b641f8bde@fb.com>
Cc: abe273e683b91ee2efa7b6f18db3864695dfa4c3@vger.kernel.org
Signed-off-by: Fabian Frederick <3efd2a027b14fd890cd23a9ef6d1134b4e5ad850@skynet.be>
Signed-off-by: Chris Mason <e2e8c5702d8ed5f565988a1cf5bb35c9ce199e5e@fb.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs