Revert "MT#4229 custom Internal server error page"

This reverts commit eece093fd0414c9004bf0ba9bb994345eee9c90d.

Otherwise fails with:

| Starting NGCP-Panel Webapp: ngcp_panel_fastcgi:Can't locate Convert/Ascii85.pm in your Perl library.  You may need to install it
| from CPAN or another repository.  Your library paths are:
|   /etc/perl
|    /usr/local/lib/perl/5.14.2
|    /usr/local/share/perl/5.14.2
|    /usr/lib/perl5
|    /usr/share/perl5
|    /usr/lib/perl/5.14
|    /usr/share/perl/5.14
|    /usr/local/lib/site_perl
|    .
|
| BEGIN failed--compilation aborted at /usr/share/perl5/NGCP/Panel/Controller/Root.pm line 5.
| Compilation failed in require at /usr/share/perl5/Catalyst/Utils.pm line 308.
| Compilation failed in require at /usr/share/perl5/Module/Runtime.pm line 317.
|  at /usr/share/perl5/Catalyst/ScriptRunner.pm line 50
| error ... failed!

because Convert::Ascii85 isn't available yet in our repositories,
therefore revert to fix broken trunk.

Acked-by: Andreas Granig <agranig@sipwise.com>
Git-Dch: Ignore