Don't symlink pip on Fedora.

* modules/pip/manifests/init.pp: Fedora installs /usr/bin/pip and
thus doesn't need a symlink there like CentOS and RHEL do.

Change-Id: I2da3d5ed11db94da3ee2c3c7cae96c76e124dbd5
Reviewed-on: https://review.openstack.org/34081
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins