4316952 ufs_fault_v should not attempt to queue more then 1 handler for a failure event

[owen.robe...@sun.com]

Author: owenr
Repository: /hg/onnv/onnv-gate
Revision: 492ae9b21637b4b4c3e19d1556772aae3284a6f8
Log message:
4316952 ufs_fault_v should not attempt to queue more then 1 handler for a 
failure event
6350587 threads blocked in cv_wait_sig after a "forced" unmount on error never 
woken up

Files:
        update: usr/src/uts/common/fs/ufs/ufs_lockfs.c
        update: usr/src/uts/common/fs/ufs/ufs_panic.c