[ccache] ccache 2.2

[tridge at samba.org]

I've released ccache 2.2. Changes include:

 - added a test suite
 - better integration with distcc
 - added CCACHE_PREFIX option
 - disabled hard links by default
 - recognise some more gcc options (eg. profiling)
 - added --ccache-skip option

Cheers, Tridge