Bug 24367: Resolve other uninitialized warns in Search.pm

Bug 24367: Resolve other uninitialized warns in Search.pm

Use of uninitialized value in hash element at /usr/share/koha/C4/Search.pm line 2074.
Use of uninitialized value in hash element at /usr/share/koha/C4/Search.pm line 2137.
Use of uninitialized value in concatenation (.) or string at /usr/share/koha/C4/Search.pm line 2189.
Use of uninitialized value in hash element at /usr/share/koha/C4/Search.pm line 2213.
Use of uninitialized value in hash element at /usr/share/koha/C4/Search.pm line 2215.
Use of uninitialized value in hash element at /usr/share/koha/C4/Search.pm line 2225.
Use of uninitialized value in hash element at /usr/share/koha/C4/Search.pm line 2226.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>