test-merge-tool: Make sure no hgmerge can be found in $PATH
The merge tool selecting algorithm is hardcoded to look for hgmerge in $PATH
before it falls back to use internal merge. This fixes the test for this
fallback to be tolerant to existing hgmerges.
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
% merge heads
HG_FILE l
HG_MY_ISLINK 1
HG_OTHER_ISLINK 0
HG_BASE_ISLINK 0
merging l
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
% merge working directory
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
HG_FILE l2
HG_MY_ISLINK 1
HG_OTHER_ISLINK 0
HG_BASE_ISLINK 0
merging l2
0 files updated, 1 files merged, 0 files removed, 0 files unresolved