Revert "apt-get update before installing buildDepends."

This reverts commit b89c00ae0a23de73bbe43741e25421b59049d47a.

Conflicts:

	git_app_builder/dxapp.json
	git_applet_builder/dxapp.json
	tarball_app_builder/dxapp.json
	tarball_applet_builder/dxapp.json