[migractions] Don't silently ignore errors when installing sql procedures If we're going to ignore errors, at least be loud about it. sqlexec already wraps the sql execution in a try/except block, so we were never going to catch any exceptions in the caller. Check the return value instead. Closes #3459618.

usr/bin/cubicweb-ctl usr/bin/
usr/lib/PY_VERSION/*-packages/cubicweb/cwctl.py
../cubicweb-ctl.bash_completion etc/bash_completion.d/cubicweb-ctl