e2fsck: handle multiple *ind block collisions with critical metadata

e2fsck: handle multiple *ind block collisions with critical metadata

An earlier patch tried to detect indirect blocks that conflicted with
critical FS metadata for the purpose of preventing corrections being
made to those indirect blocks.  Unfortunately, that patch cannot
handle more than one conflicting *ind block per file; therefore, use
the ref_block parameter to test the metadata block map to decide if
we need to avoid fixing the *ind block when we're iterating the
block's entries.  (We have to iterate the block to capture any blocks
that the block points to, as they could be in use.)

As a side note, in 1B we'll reallocate all those conflicting *ind
blocks and restart fsck, so the contents will be checked eventually.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>