move email variables into block where they are used

Author: JoshMcCullough

README.md

@@ -100,4 +100,5 @@ auth_jwt_validate_email off;
 ```
 By default, the module will attempt to validate the email address field of the JWT, then set the x-email header of the
 session, and will log an error if it isn't found.  To disable this behavior, for instance if you are using a different
-user identifier property such as 'sub', set `auth_jwt_validate_email` to the value `off`.
+user identifier property such as `sub`, set `auth_jwt_validate_email` to the value `off`. _Note that this flag may be 
+renamed to `auth_jwt_extract_email` in a future release._

src/ngx_http_auth_jwt_module.c

@@ -160,8 +160,6 @@ static ngx_int_t ngx_http_auth_jwt_handler(ngx_http_request_t *r)
 	jwt_t *jwt = NULL;
 	int jwtParseReturnCode;
 	jwt_alg_t alg;
-	const char* email;
-	ngx_str_t email_t;
 	time_t exp;
 	time_t now;
 	ngx_str_t auth_jwt_algorithm;
@@ -266,14 +264,16 @@ static ngx_int_t ngx_http_auth_jwt_handler(ngx_http_request_t *r)
 
 	if (jwtcf->auth_jwt_validate_email == 1)
 	{
-		email = jwt_get_grant(jwt, "emailAddress");
+		const char* email = jwt_get_grant(jwt, "emailAddress");
+		
 		if (email == NULL)
 		{
 			ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "the jwt does not contain an email address");
 		}
 		else
 		{
-			email_t = ngx_char_ptr_to_str_t(r->pool, (char *)email);
+			ngx_str_t email_t = ngx_char_ptr_to_str_t(r->pool, (char *)email);
+
 			set_custom_header_in_headers_out(r, &emailHeaderName, &email_t);
 		}
 	}