Fix two bugs affecting OPAC RSS operation

Fix two bugs affecting OPAC RSS operation

OPAC RSS functionality was buggish:

1. Library Name from syspref wasn't properly displayed.
2. Filename for query result caching was containing (sometime)
   a / character preventing cache file creation.

It remains that in Zebra mode, SimpleSearch returns a resultset
which is diffrent from the one returned by opac-search.pl: less records.
It works correctly in NoZebra mode.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Joshua Ferraro <jmf@liblime.com>