Fix file attributes

This branch contains the following fixes/improvements.

• Fix setting i_flags
• Fix wrong operator in xvattr.h
• Fix fchange macro in zpl_ioctl_setflags()
• Added configure check to use inode_set_flags()
• Added a test case for chattr for better test coverage

Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #5486
Closes #5470
Closes #5469