builddependencies: don't add dependency on revision outside input set
This was already handled in the single-successor case, but had been
missed in the multiple-successors case.
Note that there seems to be a copy of builddependencies() in the
topics extension. I don't use topics more than I have to, so I'll let
someone else fix that code.
#require test-repo
$ checkflake8() {
> if ! (which flake8 > /dev/null); then
> echo skipped: missing tool: flake8;
> exit 80;
> fi;
> };
$ checkflake8
Copied from Mercurial core (60ee2593a270)
$ cd "`dirname "$TESTDIR"`"
run flake8 if it exists; if it doesn't, then just skip
$ hg files -0 'set:(**.py or grep("^#!.*python")) - removed()' \
> -X hgext3rd/evolve/thirdparty \
> 2>/dev/null \
> | xargs -0 flake8