Removed unclear sentence in mod-http2 doc.

Lajos Veres asked in docs@ to review the removed
sentence since it was unclear. Instead of reworking it,
I preferred to remove it since the Context is already
specified in the related section of the Directive.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1777324 13f79535-47bb-0310-9956-ffa450edef68