Memento Exception when page is not found

[Stephan Doerfel]

The memento button often yields a 500 error and shows this exception to the user: Internal Server Error: org.bibsonomy.common.exceptions.InternServerException: Could not retrieve archived version for <URL> ...

a) Please catch the exception and present a meaningfull message to the user

b) Please make sure that this is no longer logged in the error log

c) Sometimes the exception is thrown even though there is a valid entry in the wayback machine. This behavior is however not consistent, i.e. refreshing the error page a few times eventually yields the result in the wayback machine. Please investigate, why the error is sometimes thrown (maybe timeouts or some quota on the wayback machine?)

[Daniel Zoller]

no internal server exception when the time gate can't find an archived version instead displaying error page with error message

fixes #2073

→ <<cset 7d5531a9604f>>