cpan-base: Add vardepvalue to get_perl_version function
* without this bitbake -S perf shows following error:
ERROR: Bitbake's cached basehash does not match the one we just generated
(/OE/oe-core/meta/recipes-kernel/perf/perf.bb.do_package)!
if you run it twice, once without perl in sysroot and once with perl
already built
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
