ceph: move static keyword to the front of declarations

Move the static keyword to the front of declarations of
snap_handle_length, handle_length and connected_handle_length,
and resolve the following compiler warnings that can be seen
when building with warnings enabled (W=1):

fs/ceph/export.c:38:2: warning:
  ‘static’ is not at beginning of declaration [-Wold-style-declaration]

fs/ceph/export.c:88:2: warning:
  ‘static’ is not at beginning of declaration [-Wold-style-declaration]

fs/ceph/export.c:90:2: warning:
  ‘static’ is not at beginning of declaration [-Wold-style-declaration]

Signed-off-by: Krzysztof Wilczynski <kw@linux.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>