Update deletepattern in redis lib to return the number of deleted keys

lib/redis/redis.js

@@ -138,11 +138,13 @@ module.exports = {
 
 	deletePattern: (pattern) => {
 		return new Promise((resolve, reject) => {
+			let totalDeleted = 0;
 			const stream = sharedClient.scanStream({
 				match: pattern
 			});
 			stream.on('data', (keys) => {
 				if (keys.length > 0) {
+					totalDeleted += keys.length;
 					const pipeline = sharedClient.pipeline();
 					for (let i = 0; i < keys.length; i++) {
 						pipeline.del(keys[i]);
@@ -151,7 +153,7 @@ module.exports = {
 				}
 			});
 			stream.on('end', () => {
-				resolve();
+				resolve(totalDeleted);
 			});
 			stream.on('error', (err) => {
 				reject(err);