Bug 17869: Don't show pick-up library for list of holds in OPAC account when there...

Bug 17869: Don't show pick-up library for list of holds in OPAC account when there is only one branch

This patch modifies the user summary page in the OPAC so that the
"pick up location" column isn't shown in the table of holds if there is
only one library defined.

To test, apply the patch and log into the OPAC as a user with one or
more holds.

 - In a system with more than one library defined the "Holds" tab of
   opac-user.pl should show a "Pick up location" column.

 - In a system with only one library defined there should be now "Pick
   up location" column.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>