Bug 7413: OPAC bootstrap theme changes

Bug 7413: OPAC bootstrap theme changes

This patch makes opac-user.pl and the bootstrap version of opac-user.tt
handle the new renewal error "too_soon".

To test:
1) Set global syspref "opacthemes" to bootstrap.
2) Set global syspref "OpacRenewalAllowed" to Allow.
3) Test the same things as in previous patch, this time for the OPAC
    summary page.

Sponsored-by: Hochschule für Gesundheit (hsg), Germany
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>