[DRE-maint] Bug#880276: caused by the fix of #842432

[Cédric Boutillier]

Control: retitle -1 test using GCM with IV option fails after fix for CVE-2016-7798 

Hi,

Checking when the package stopped to pass autopkgtests, I could trace
the issue to the fix of #842432 in ruby2.3 to avoid IV reuse in GCM
mode. The title of the failing test
  test_ciphertext_encrypted_with_v2_decrypts_with_v2_gcm_iv_option
also suggests it is the source of the problem.

Cédric