MB-11022 correctly recognize errors from lhttpc_client

lhttpc_client uses erlang:error to throw some errors which adds the call
stack to the error.

Change-Id: I75a93be0cdc6f77aa13437462bfd1e9606c26bd6
Reviewed-on: http://review.couchbase.org/37759
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>