Bug 7337 - "Debarred Until" display in the opac tells patrons they are debarred until...

Bug 7337 - "Debarred Until" display in the opac tells patrons they are debarred until the year 9999

This patch copies the debarred handling method from circulation.pl for
use on opac-user.pl so that debarred dates and comments can be handled
properly.

I have slightly reworded the message in the OPAC and on circulation.pl
to make the display of the debarred comment a little clearer.

Revision adds missing handling of debarred status with regard to
renewal operations. Renew links and buttons were not being hidden
from debarred users.

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Renewal buttons are gone, message looks good.

liz@koha-deb:~/kohaclone$ prove xt
xt/permissions.t .. ok
xt/tt_valid.t ..... ok
All tests successful.
Files=2, Tests=27,  9 wallclock secs ( 0.05 usr  0.01 sys +  8.28 cusr  0.08 csys =  8.42 CPU)
Result: PASS

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>