Bug 21716: Escape publisher in item search

Bug 21716: Escape publisher in item search

To prevent endless processing errors.

To test:

* create a biblio with a publisher with a backslash - i.e. 260$b with
graham\lineham
* do an item search that will include that title in the results
* wait forever, because it won't work.
* apply this patch
* repeat steps, notice that you
    a. get results
    b. your result is listed with it's correct publisher
* rejoice

Signed-off-by: Hayley Mapley <hayleymapley@catalyst.net.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit fbeb22802f41f8daf99498303146d1916c851507)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>