Fixes 1.7 assets downloading

When downloading the minecraft assets, the minecraft version check is incorrect for 1.7 packs. The pack version is checked instead. This causes 1.7 packs to attempt the old download method, which obviously fails.
Merge pull request #639 from Watchful1/master

Fixes 1.7 assets downloading
Merge branch 'master' of https://github.com/Slowpoke101/FTBLaunch

Conflicts:
	src/net/ftb/gui/LaunchFrame.java