Bug 21318: Add control number as an option to search authority using Z39.50

Bug 21318: Add control number as an option to search authority using Z39.50

1) Apply the patch
2) Go to administration and set up a z39.50 authority server, which does
support searching by control number (use attribute 12), you can use czech
national library server:
host: aleph.nkp.cz
port: 9991
base: aut-utf
format: MARC21
encoding: UTF-8
3) Try to find an authority by control number using z39.50 - if you use the server
recomended in point 2) there is web access to the base at
http://aleph.nkp.cz/eng/aut

Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Fixed a typo in a code comment and a whitespace issue in the template.

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>