HAMMER: Fix a couple of minor non-corrupting bugs in HAMMER.

HAMMER: Fix a couple of minor non-corrupting bugs in HAMMER.

* Fix a few cases where the kmalloc space for hammer inodes can become
  exhausted.  Add calls to hammer_inode_waitreclaims() in several places
  where modified inodes can build up without the related vnodes
  necessarily being VOP_OPEN()'d or VOP_CLOSE()'d.

* Fix a deadlock which can occur in fsync().  fsync() was holding the vnode
  lock while waiting for the inode to sync.  The inode sync can be held up
  indefinitely by dependancies on other vnodes, so holding the lock can
  result in a deadlock.

* Fix a bug where ap->a_ctllen test results were being ignored.  This
  path is only used by mountd.

Reported-by: 	Francois Tigeot <ftigeot@wolfpond.org>,
		Damian Lubosch <dl@pless.xiqit.de>