merge: make internal merge fail cleanly on symlinks
Simplemerge is not symlink aware and will never do the the right thing on
symlinks. It would read the symlink as a file and abort with 'No such file or
directory' on dangling symlinks.
Instead, internal:merge now simply fails to merge symlinks.
$ "$TESTDIR/hghave" pyflakes || exit 80
$ cd "`dirname "$TESTDIR"`"
$ pyflakes mercurial hgext 2>&1 | "$TESTDIR/filterpyflakes.py"
hgext/inotify/linux/__init__.py:*: 'from _inotify import *' used; unable to detect undefined names (glob)