Fix bug with continued HTTP sessions

THe handling of when to allow an HTTP keepalive header was incorrect in
a refactor that happened a while back.  This corrects it.

Change-Id: I0a19803ab37415aa3ef3c705e75946a64689660d
Signed-off-by: Ed Tanous <ed.tanous@intel.com>
diff --git a/crow/include/crow/http_parser_merged.h b/crow/include/crow/http_parser_merged.h
index 262e023..030e8a4 100644
--- a/crow/include/crow/http_parser_merged.h
+++ b/crow/include/crow/http_parser_merged.h
@@ -2292,7 +2292,7 @@
     }
   }
 
-  return static_cast<int>(!http_message_needs_eof(parser)) == 0;
+  return !http_message_needs_eof(parser);
 }
 
 inline const char *http_method_str(enum http_method m) {