[horde] force http channel

[A. Schulze]

Dark Drq:

> Is there is a problem with the cert?

ssllabs say "no":  
https://www.ssllabs.com/ssltest/analyze.html?d=pear.horde.org


> $ wget https://pear.horde.org/rest/
> --2016-07-01 00:38:31--  https://pear.horde.org/rest/
> Resolving pear.horde.org (pear.horde.org)... 200.46.208.218
> Connecting to pear.horde.org (pear.horde.org)|200.46.208.218|:443...  
> connected.
> ERROR: cannot verify pear.horde.org's certificate, issued by  
> '/C=US/O=Let\'s Encrypt/CN=Let\'s Encrypt Authority X3':

> Unable to locally verify the issuer's authority.
looks like your certificate store misses "DST Root CA X3"

Andreas