Adds ccache to jenkins slaves.
Adds ccache to jenkins slaves.

Creates symlinks in /usr/local/bin to automatically use ccache
and also fix some spacing issues. Symlink files depend on ccache
to prevent dangling links.

Addresses bug 989724.

Change-Id: I889ef377efd9a512dfec78c3c417931a764e514c

open-switch/infra_puppet-jenkins,open-switch/infra_puppet-jenkins