Fix a few warnings that -Wnull-conversion of a future clang will complain about.

crypto/rsa_private_key_mac.cc

Index: crypto/rsa_private_key_mac.cc
diff --git a/crypto/rsa_private_key_mac.cc b/crypto/rsa_private_key_mac.cc
index 8dcf14a61fc91b32b93ae1e2b45764e9432e2729..e74b78ad5d71031f6cd8d081f9a22dbe64f480a3 100644
--- a/crypto/rsa_private_key_mac.cc
+++ b/crypto/rsa_private_key_mac.cc
@@ -71,7 +71,8 @@ RSAPrivateKey* RSAPrivateKey::CreateFromPrivateKeyInfo(
 
   CSSM_KEY_SIZE key_size;
   CSSM_RETURN crtn;
-  crtn = CSSM_QueryKeySizeInBits(GetSharedCSPHandle(), NULL, &key, &key_size);
+  crtn = CSSM_QueryKeySizeInBits(
+      GetSharedCSPHandle(), CSSM_INVALID_HANDLE, &key, &key_size);
   if (crtn) {
     NOTREACHED() << "CSSM_QueryKeySizeInBits failed: " << crtn;
     return NULL;
@@ -133,8 +134,8 @@ RSAPrivateKey* RSAPrivateKey::CreateFromPrivateKeyInfo(
   public_key->KeyHeader.KeyAttr = CSSM_KEYATTR_EXTRACTABLE;
   public_key->KeyHeader.KeyUsage = CSSM_KEYUSE_ANY;
 
-  crtn = CSSM_QueryKeySizeInBits(GetSharedCSPHandle(), NULL, public_key,
-                                 &key_size);
+  crtn = CSSM_QueryKeySizeInBits(
+      GetSharedCSPHandle(), CSSM_INVALID_HANDLE, public_key, &key_size);
   if (crtn) {
     DLOG(ERROR) << "CSSM_QueryKeySizeInBits failed " << crtn;
     return NULL;