From the source code (get from apt-get source) of openssl-1.0.2g, I find

SSL_CTX_clear_options(ctx, op):
  op &= ~SSL_OP_NO_SSLv3
  return (ctx->options &= ~op)
SSL_CTX_set_options(ctx, op):
  op |= SSL_OP_NO_SSLv3
  return (ctx->options |= op)

which differs from the official code repos:

SSL_CTX_clear_options(ctx, op):
  return (ctx->options &= ~op)
SSL_CTX_set_options(ctx, op):
  return (ctx->options |= op)

This difference is introduced by debian-specific patch:

     case SSL_CTRL_OPTIONS:
+        larg|=SSL_OP_NO_SSLv3;
         return (ctx->options |= larg);
     case SSL_CTRL_CLEAR_OPTIONS:
+        larg&=~SSL_OP_NO_SSLv3;
         return (ctx->options &= ~larg);