Bump metro to 0.43.4

Summary: New version for metro.

Reviewed By: rafeca

Differential Revision: D9148300

fbshipit-source-id: 77a520aba8be7111da0bf71898684cd6922ff556

package.json

@@ -170,10 +170,10 @@
     "graceful-fs": "^4.1.3",
     "inquirer": "^3.0.6",
     "lodash": "^4.17.5",
-    "metro": "^0.43.3",
-    "metro-babel-register": "^0.43.3",
-    "metro-core": "^0.43.3",
-    "metro-memory-fs": "^0.43.3",
+    "metro": "^0.43.4",
+    "metro-babel-register": "^0.43.4",
+    "metro-core": "^0.43.4",
+    "metro-memory-fs": "^0.43.4",
     "mime": "^1.3.4",
     "minimist": "^1.2.0",
     "mkdirp": "^0.5.1",