MFC r264480: mergemaster: Avoid "/var/tmp/temproot disappeared" if there is
nothing to compare.

Because of the change to find in SVN r253886, the entire temproot would be
deleted if it became empty, leading to a confusing message "*** FATAL ERROR:
The temproot directory ${TEMPROOT} has disappeared!"

Note that mergemaster does not do anything useful in this situation anyway
(e.g. put IGNORE_FILES="/etc/group /etc/master.passwd" in
/etc/mergemaster.rc and run mergemaster -p).

As noted in that commit, add -mindepth 1.

PR: bin/188485
Submitted by: David Boyd

MFC: r258456

Fix mergemaster -U by forcing FreeBSD 9 compatiblity in mtree when mtree is
nmtree.

The mtree output used by mergemaster in this case was clearly not meant for
computer consumption and an approach based on -f <file1> -f <file2> would
probably be a better idea, but this is a minimal change.

Approved by: re (glebius)

MFC r264480: mergemaster: Avoid "/var/tmp/temproot disappeared" if there is
nothing to compare.

Because of the change to find in SVN r253886, the entire temproot would be
deleted if it became empty, leading to a confusing message "*** FATAL ERROR:
The temproot directory ${TEMPROOT} has disappeared!"

Note that mergemaster does not do anything useful in this situation anyway
(e.g. put IGNORE_FILES="/etc/group /etc/master.passwd" in
/etc/mergemaster.rc and run mergemaster -p).

As noted in that commit, add -mindepth 1.

PR: bin/188485
Submitted by: David Boyd

MFC: r258456

Fix mergemaster -U by forcing FreeBSD 9 compatiblity in mtree when mtree is
nmtree.

The mtree output used by mergemaster in this case was clearly not meant for
computer consumption and an approach based on -f <file1> -f <file2> would
probably be a better idea, but this is a minimal change.

Approved by: re (glebius)