fs: btrfs: Fix usage of uninitialized variables

The variable res should be initialized to 0 in these functions,
because if the searched key is not found, the variable is used
uninitialized.

Reported-by: Coverity (CID: 167335)
Reported-by: Coverity (CID: 167336)
Reported-by: Coverity (CID: 167337)
Signed-off-by: Marek Behun <marek.behun@nic.cz>
3 files changed