[misc] bump socket.io to 0.9.19 for node7+ support

Signed-off-by: Jakob Ackermann <das7pad@outlook.com>

services/real-time/npm-shrinkwrap.json

@@ -1560,9 +1560,9 @@
       "dev": true
     },
     "socket.io": {
-      "version": "0.9.16",
-      "from": "socket.io@0.9.16",
-      "resolved": "https://registry.npmjs.org/socket.io/-/socket.io-0.9.16.tgz",
+      "version": "0.9.19",
+      "from": "socket.io@0.9.19",
+      "resolved": "https://registry.npmjs.org/socket.io/-/socket.io-0.9.19.tgz",
       "dependencies": {
         "redis": {
           "version": "0.7.3",

services/real-time/package.json

@@ -34,7 +34,7 @@
     "request": "^2.88.0",
     "session.socket.io": "^0.1.6",
     "settings-sharelatex": "^1.1.0",
-    "socket.io": "0.9.16",
+    "socket.io": "^0.9.19",
     "socket.io-client": "^0.9.16"
   },
   "devDependencies": {