Remove development artifacts.

The issue was discovered on the x86/64 when attempting to include
libcrypto inside another shared library.  A relocation of type
R_X86_64_PC32 was generated which causes a linker error.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6595)