ParseGetLine: don't treat a zero byte as end of buffer if P_end says it isn't.
Consume up to next newline, and issue a parse warning.
If no newline found before P_end, carry on as before.
The r254167 moved initialization of the sleepqueues before the witness
is operational.  init_sleepqueues() initializes 256 mutexes, which,
due to witness still being cold, started to overflow the pending_locks
array.

As stated in the reported panic message, increase WITNESS_PENDLIST
from 768 to 1024, which provides space for additional 256 locks.

Reported by:	many
Tested by:	rakuco, bdrewery
Add in missing m_free()'s during error conditions.