compat: add wrapper for obsolete.createmarkers() that accepts "operation" arg
I want to start passing the operation argument, but hg < 4.3 does not
support it, so we need a compat wrapper. For older hg, the operation
is simply ignored.
#require test-repo pyflakes
Copied from Mercurial core (60ee2593a270)
$ cd "`dirname "$TESTDIR"`"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ hg locate 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
> | xargs pyflakes 2>/dev/null