In the 'found' case for ext2_lookup() the underlying bp's data was
being accessed after the bp had been releaed. A simple move of the
brelse() solves the problem.
The PR reports that this caused panics running the GDB testsuite unless
NO_GEOM is configured.
PR: 44060
Reported by: Mark Kettenis <kettenis@chello.nl>
MFC after: 3 days