test fixes for Solaris 2.6
Solaris 2.6's stock sed doesn't support alternatives in regular
expression. We workaround by breaking up the regexp.
Is there an error message when trying to diff non-existing files?
not: No such file or directory
found: No such file or directory
Is there an error message when trying to add non-existing files?
not: No such file or directory
found: No such file or directory