check_http: realloc(): invalid next size when using chunked encoding

[waja]

In Debian we got reported this issue: https://bugs.debian.org/1029934:

$ /usr/lib/nagios/plugins/check_http -H www.bootc.net --ssl --sni 
realloc(): invalid next size
Aborted

When run in verbose mode it's clear that the site uses HTTP chunked
encoding, and this is potentially the cause of the problem.

Please go ahead and use the URI/hostname in my example above to help to
reproduce this bug.

[RincewindsHat]

should be fixed by #1830