bug 2628: fixing test script to deal with DESTDIR in Makefile.PL

bug 2628: fixing test script to deal with DESTDIR in Makefile.PL

Recently, there were changes to the Makefile.PL to make it install in a
DESTDIR that the OS (debian) may choose. This broke the test suite.
Since we're not installing the stuff in the t/ directory, we need to
ignore the DESTDIR specifiation before we write the test-config.txt.
So, this patch adds a call to the _strip_destdir function for all
directories written to the t/test-config.txt file.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>