merge: make test for fast-forward merge stricter (issue619)
don't allow merging with an ancestor
fix != on contexts
add a test
adding a
adding b
copy .hg/patches to .hg/patches.1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
M b
a
b
merging with queue at: .hg/patches.1
applying rm_a
Now at: rm_a
b
Patch queue now empty