Empty strings in oils_i18n_gettext() throw i18n errors

Empty strings in oils_i18n_gettext() throw i18n errors

When you run 'make newpot', if you have an empty string in an
oils_i18n_gettext() function, you'll see errors like:

Error in line 1712 of SQL source file: 'NoneType' object has no attribute 'group'

This satisfies the i18n build process and also serves as a
more evident placeholder for expanded descriptions if someone
feels so inclined in the future.

git-svn-id: svn://svn.open-ils.org/ILS/branches/rel_2_1@20140 dcc99617-32d9-48b4-a31d-7c20da2025e4