libotutil: Link to crypto libs

libotutil: Link to crypto libs

The checksum utils uses the crypto lib, but we're not explicitly linking
to it. I think this is why the CI got this error when using openssl
on debian, during ostree binary linking:

/usr/bin/ld: ./.libs/libotutil.a(libotutil_la-ot-checksum-utils.o): undefined reference to symbol 'EVP_DigestInit_ex@@OPENSSL_3.0.0'
/usr/bin/ld: /lib/x86_64-linux-gnu/libcrypto.so.3: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status