Don't call ERR_clear_system_error in so many places.

We've got it in entry points. That should be sufficient. (Do we even need it
there?)

Change-Id: I39b245a08fcde7b57e61b0bfc595c6ff4ce2a07a
Reviewed-on: https://boringssl-review.googlesource.com/8127
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 8e9b196..ec30dcf 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -559,6 +559,7 @@
   ssl->rwstate = SSL_NOTHING;
   /* Functions which use SSL_get_error must clear the error queue on entry. */
   ERR_clear_error();
+  ERR_clear_system_error();
 
   if (ssl->handshake_func == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_CONNECTION_TYPE_NOT_SET);
@@ -665,6 +666,7 @@
   ssl->rwstate = SSL_NOTHING;
   /* Functions which use SSL_get_error must clear the error queue on entry. */
   ERR_clear_error();
+  ERR_clear_system_error();
 
   if (ssl->handshake_func == NULL) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_UNINITIALIZED);