Update RSATest.BadKey to use a plausible key size

One less thing to update when we next bump the minimum.

Bug: 607
Change-Id: I50bd01b14499a7ed7904a5e111c3e1df57eaa144
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/61645
Reviewed-by: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

crypto/rsa_extra/rsa_test.cc

diff --git a/crypto/rsa_extra/rsa_test.cc b/crypto/rsa_extra/rsa_test.cc
index e332cdf..4d34fc9 100644
--- a/crypto/rsa_extra/rsa_test.cc
+++ b/crypto/rsa_extra/rsa_test.cc
@@ -636,7 +636,7 @@
   ASSERT_TRUE(BN_set_word(e.get(), RSA_F4));
 
   // Generate a bad key.
-  ASSERT_TRUE(RSA_generate_key_ex(key.get(), 512, e.get(), nullptr));
+  ASSERT_TRUE(RSA_generate_key_ex(key.get(), 2048, e.get(), nullptr));
   ASSERT_TRUE(BN_add(key->p, key->p, BN_value_one()));
 
   // Bad keys are detected.