Removed extra missing script from package.json

Summary:
The generate script file was removed but the package.json file was never update.
I'm doing it here.

Changelog:
[Internal] [Changed] - Removed extra missing script from package.json

Reviewed By: ShikaSD

Differential Revision: D31171736

fbshipit-source-id: 5b9474651d10374ccbb0b06f2c83bc34da01a179

package.json

@@ -39,7 +39,6 @@
     "rn-get-polyfills.js",
     "scripts/compose-source-maps.js",
     "scripts/find-node.sh",
-    "scripts/generate-specs.sh",
     "scripts/generate-specs-cli.js",
     "scripts/ios-configure-glog.sh",
     "scripts/launchPackager.bat",