use internal merge tool when specified for a merge-pattern in hgrc
It is possible to specify in the hgrc file that one of the internal merge
tools (internal:fail, internal:local or internal:other) be used for
performing merges on files matching a given pattern. However, this setting
is not being acted upon (the merge tool is not found). This patch fixes that.
created new head
digraph G {
-1 -> 0
0 -> 1
0 -> 2
2 -> 3
1 -> 3
}