client: Fix parsing of xattr namespace in removexattr

client: Fix parsing of xattr namespace in removexattr

To match the kernel ceph client, as mentioned by the inline comments,
remove the comparison with "system." xattr namespace in removexattr()
code path. This is in preparation to handle the case where POSIX ACL
xattrs are treated differently by kernel during removexattr operation.

ref: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/ceph/xattr.c#n21

Signed-off-by: Anoop C S <anoopcs@cryptolab.net>