install-qibuild.sh: small bug fixes
install-qibuild.sh: small bug fixes

Use ~/.local/bin instead of ~/.bin
(used by distutils for other python scripts when using --user,
 so this makes a bit more sense)

Also, fix using install-qibuild.sh on distros where
/usr/bin/python is python3.

Change-Id: I7333ef576dbc0d0ae3935489b6ba015d1d6a6b05

aldebaran/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild