fix kicad-install.sh so it doesn't ask for launchpad credentials

this was mentioned on the list.  there is a command in the kicad-install shell script that bombs out if the user doesn't have launchpad credentials entered.  There is no reason for this.

this line means that a person wanting to download and install kicad will be told they can't, until they can figure out how to get a launchpad ID and enter it into bzr.  Taking out this line fixes that.

if we want people to install kicad, we need to take out roadblocks like this one!