[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/lib/PY_VERSION/*-packages/cubicweb/server/
usr/lib/PY_VERSION/*-packages/cubicweb/hooks/
usr/lib/PY_VERSION/*-packages/cubicweb/sobjects/
usr/lib/PY_VERSION/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/