caches: fix automatic warming trigger
The caches were supposed to get warmed when we receive a push. However the
transaction created when we -issue- a push use a similar name and was confusing
the detection.
We now properly detect the case.
#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