libwebsockets

coverity: 231926: clear false positive by showing coverity what it wants to see

We can't get here without testing for COLON_PATH existing in http2.c as part of
the h2spec pass code.

		if (!lws_hdr_total_length(h2n->swsi, WSI_TOKEN_HTTP_COLON_PATH) ||
		    !lws_hdr_total_length(h2n->swsi, WSI_TOKEN_HTTP_COLON_METHOD) ||
		    !lws_hdr_total_length(h2n->swsi, WSI_TOKEN_HTTP_COLON_SCHEME) ||
		     lws_hdr_total_length(h2n->swsi, WSI_TOKEN_HTTP_COLON_STATUS) ||
		     lws_hdr_extant(h2n->swsi, WSI_TOKEN_CONNECTION)) {
			lws_h2_goaway(wsi, H2_ERR_PROTOCOL_ERROR,
				      "Pseudoheader checks");
			break;
		}

So there is no issue.  But show Coverity what it wants so we don't keep getting this
false positive reported by different coverity users.