Fix bug where sage-cleaner does not quit under certain circumstances
Solaris requires a path argument to find
Trac #15458: "make distclean" fails on Solaris

From the "make disclean" output:
{{{
find -name '*.pyc' | xargs rm -f
find: illegal option -- n
find: [-H | -L] path-list predicate-list
find -name '*.pyx' | sed 's/pyx$/c/' | xargs rm -f
find: illegal option -- n
find: [-H | -L] path-list predicate-list
find -name '*.pyx' | sed 's/pyx$/cpp/' | xargs rm -f
find: illegal option -- n
find: [-H | -L] path-list predicate-list
}}}

URL: http://trac.sagemath.org/15458
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s):
Trac #15457: sage-cleaner does not quit

If there are files in `DOT_SAGE/temp/HOSTNAME` then the sage cleaner
process never stops. Note that Sage temp files must(!) be under
`DOT_SAGE/temp/HOSTNAME/<pid>`.

URL: http://trac.sagemath.org/15457
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s):