tests/testlib/push-checkheads-util.sh

repair: move check for existing transaction earlier

Several benefits:

 * Gets close the comment describing it
 * Splits off unrelated comment about "backup" argument
 * Error checking is customarily done early
 * If we added an early return to the method, it would still
   consistently fail if there was an existing transaction (so
   we would find and fix that case quickly)

One test needs updating with for this change, because we no longer
create the backup bundle before we fail. I don't see much reason to
create that backup bundle. If some command was adding content and then
trying to strip it as well within the transaction, we would have a
backup for the user, but the risk of that not being discovered in
development seems very small.

# setup config and various utility to test new heads checks on push

cat >> $HGRCPATH <<EOF
[ui]
# simpler log output
logtemplate ="{node|short} ({phase}): {desc}\n"

[phases]
# non publishing server
publish=False

[extensions]
# we need to strip some changeset for some test cases
strip=

[experimental]
# enable evolution
evolution=all

[alias]
# fix date used to create obsolete markers.
debugobsolete=debugobsolete -d '0 0'
EOF

mkcommit() {
   echo "$1" > "$1"
   hg add "$1"
   hg ci -m "$1"
}

getid() {
   hg log --hidden --template '{node}\n' --rev "$1"
}

setuprepos() {
    echo creating basic server and client repo
    hg init server
    cd server
    mkcommit root
    hg phase --public .
    mkcommit A0
    cd ..
    hg clone server client
}