xserver lock order violation

xserver lock order violation

individual volume locks are pretty far down, well after afs_xserver.

afs_SetupVolume (with tv->lock)-> InstallUVolumeEntry-> afs_GetServer.

Install*Volume is careful to protect against recursing into the volume
lock via ResetVolumeInfo. Unfortunately, GetServer acquires xserver,
and then if it needs to call GetCapabilities, it drops and reacquires
xserver.

turns out the volume locks weren't protecting much. they also aren't
grabbed before xvolume is dropped. fine, so, restructure to do all the
work, then merge the result.

Reviewed-on: http://gerrit.openafs.org/5303
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 16dff61e148ce6893a68dda6e05e84f96fa753ac)

Change-Id: I7ca73fe9cf76e9a47cdccfc6cf0e9188fce9f5a6
Reviewed-on: http://gerrit.openafs.org/6309
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>