output-json-http: Add JSON support for X-Flash-Version.

Supported as a custom field.

src/output-json-http.c

@@ -92,6 +92,7 @@ typedef enum {
     HTTP_FIELD_DNT,
     HTTP_FIELD_X_FORWARDED_PROTO,
     HTTP_FIELD_X_AUTHENTICATED_USER,
+    HTTP_FIELD_X_FLASH_VERSION,
     HTTP_FIELD_ACCEPT_RANGES,
     HTTP_FIELD_AGE,
     HTTP_FIELD_ALLOW,
@@ -148,6 +149,7 @@ struct {
     { "dnt", "dnt", LOG_HTTP_REQUEST },
     { "x_forwarded_proto", "x-forwarded-proto", LOG_HTTP_REQUEST },
     { "x_authenticated_user", "x-authenticated-user", LOG_HTTP_REQUEST },
+    { "x_flash_version", "x-flash-version", LOG_HTTP_REQUEST },
     { "accept_range", "accept-range", 0 },
     { "age", "age", 0 },
     { "allow", "allow", 0 },