Fedora needs Locale::Maketext::Lexicon too

Per commit 66c45b647, install Locale::Maketext::Lexicon on Fedora to satisfy
that dependency. How did _this_ one slip by so long! Thank heavens for
tests.

Signed-off-by: Dan Scott <dscott@laurentian.ca>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>