Protect against installs with no locales

Protect against installs with no locales

Installs from source outside of tarballs may not have a built locale,
which would result in a make error and an aborted install. Protect
against that by checking for the existence of the locale install
directory before trying to copy the files into place.

In the weird case that Open-ILS/src/data/locale has been generated but
there are no files in it, protect against erroring out via the judicious
application of the - flag.

Signed-off-by: Dan Scott <dscott@laurentian.ca>