Bug 36085: Only superlibrarians can protect patrons

Bug 36085: Only superlibrarians can protect patrons

A drive-by patch which hopes to resolve bug 36085 by only allowing superlibrarians
to protect or unprotect patrons.

Test plan:
a)  prepare two koha staff users:
        1)  a superlibrarian
        2)  a user that only has permission to edit patrons
b)  when logged in as the user prepared in step a2 (non-superlibrarian),
    then go to edit any patron
        *)  note how you can set the protected yes/no radios
c)  apply the patch
d)  repeat steps a-b as this same user
        *)  note how you can now no longer see the protected yes/no radios
e)  log in as the user prepared in step a1 (superlibrarian), then repeat
    steps a-b
f)  note how the protected yes/no radios are back

Signed-off-by: Jan Kissig <jkissig@th-wildau.de>
Signed-off-by: Paul Derscheid <paul.derscheid@lmscloud.de>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>