invalid api keys cause github update to fail

[seiyria]

data:    Main.coffee:19323 - /home/kempk/kurea/src/modules/core/GitUpdateModule.coffee:148
data:    Main.coffee:19323 -                 if (data.commits.length > 0) {
data:    Main.coffee:19323 -                                 ^
data:    Main.coffee:19323 - TypeError: Cannot read property 'length' of undefined
data:    Main.coffee:19323 -   at IncomingMessage.<anonymous> (/home/kempk/kurea/src/modules/core/GitUpdateModule.coffee:119:22)
data:    Main.coffee:19323 -   at IncomingMessage.EventEmitter.emit (events.js:117:20)
data:    Main.coffee:19323 -   at _stream_readable.js:920:16
data:    Main.coffee:19323 -   at process._tickCallback (node.js:415:13)