guard created values from being optimized out (bnc#895964)

Grr, I don't understand this! Yes, it is the same as [the sqlite fix](https://github.com/sparklemotion/sqlite3-ruby/commit/dd9ded98633ece40f9794464e82bb7646028753e). But all ruby values should be in memory before and after the fix. I don't see how the compiler could have optimized away the *array*.