Fix a few more missing CBB_cleanups.

See also 1b0c438e1a0e570de18ecc7aabda3be8dea4cfa0.

Change-Id: Ifcfe15caa4d0db8ef725f8dacd0e8c5c94b00a09
Reviewed-on: https://boringssl-review.googlesource.com/7390
Reviewed-by: Emily Stark (Dunn) <estark@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/crypto/ecdsa/ecdsa_asn1.c b/crypto/ecdsa/ecdsa_asn1.c
index 3a47257..d41a536 100644
--- a/crypto/ecdsa/ecdsa_asn1.c
+++ b/crypto/ecdsa/ecdsa_asn1.c
@@ -220,6 +220,7 @@
   CBB cbb;
   if (!CBB_init(&cbb, 0) ||
       !ECDSA_SIG_marshal(&cbb, sig)) {
+    CBB_cleanup(&cbb);
     return -1;
   }
   return CBB_finish_i2d(&cbb, outp);