Bug 3326: Work around Zebra's handling of & entities

Bug 3326: Work around Zebra's handling of & entities

When using XSLT mode, the OPAC results display will show "&" instead of "&"
when Zebra is indexing in XML mode. This patch works around this by replacing
"&" with "&" and then extends the previous fix to apply to all occurrences
of "& " instead of just the first.

Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
(cherry picked from commit d52f3680f482a42cc98ad9810c011c8775d9b3ee)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>