common/cmdparse: use map::find() only a single time

common/cmdparse: use map::find() only a single time

instead of using the combo of

if (map.count(key)) {
  return map.find(key)->second;
}

just use

found = map.find(key);
if (found != map.end()) {
  return found->second;
}

to avoid repeating the lookup in the map with the same key.

Signed-off-by: Kefu Chai <kchai@redhat.com>