Btrfs: don't panic if we get an error while balancing V2
Btrfs: don't panic if we get an error while balancing V2

A user reported an error where if we try to balance an fs after a device has
been removed it will blow up.  This is because we get an EIO back and this is
where BUG_ON(ret) bites us in the ass.  To fix we just exit.  Thanks,

Reported-by: Anand Jain <720fab3a919e9ecd827b8ea6d06ecf062751adf6@oracle.com>
Signed-off-by: Josef Bacik <78b342861d821967b29f951b7366f5a0267e0c38@redhat.com>
Signed-off-by: Chris Mason <a169954b4cb1a46cee25f659d3bddfebe02b5fba@oracle.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs