Remove import/use of File::Spec::Function

It looks like the usage of these functions were removed in
in commit 0a4edb93

 ("Unified - adapt
the generation of cpuid, uplink and buildinf to use GENERATE").

This commit removes the import/use of File::Spec::Functions module as it
is no longer needed by crypto/build.info.

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5832)

(cherry picked from commit 0e34f37f)