hgmerge: various cleanups
Details:
- put temporary file names into variables
- make all temporary file names end with random part
- cleanup FileMerge handling
- do not use hardlinks in FileMerge change test (breaks on FAT)
- try harder to keep file mtime unchanged in case of failed merge
merge: warning: conflicts during merge
merging a
merging a failed!
32e80765d7fe+75234512624c+ tip
something else
=======
something
M a