nfsd4_process_open2 has become a bit long and contorted.  The following
patches break nfsd4_process_open2 into smaller functions and add comments to
describe logic flow, in preparation for delegation state.

We begin by pulling out the code that searches for conflicting open owners
into a separate function.
Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>