Miscellaneous -Wshorten-64-to-32 fixes.

Bug: 516
Change-Id: Iba2014da414658c08e42e0993912fa73848832d3
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/54945
Reviewed-by: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

ssl/bio_ssl.cc

diff --git a/ssl/bio_ssl.cc b/ssl/bio_ssl.cc
index a249889..fe83450 100644
--- a/ssl/bio_ssl.cc
+++ b/ssl/bio_ssl.cc
@@ -109,7 +109,7 @@
       // |bio->next_bio| with |ssl|'s rbio here, and on |BIO_CTRL_PUSH|. We call
       // into the corresponding |BIO| directly. (We can implement the upstream
       // behavior if it ends up necessary.)
-      bio->shutdown = num;
+      bio->shutdown = static_cast<int>(num);
       bio->ptr = ptr;
       bio->init = 1;
       return 1;
@@ -118,7 +118,7 @@
       return bio->shutdown;
 
     case BIO_CTRL_SET_CLOSE:
-      bio->shutdown = num;
+      bio->shutdown = static_cast<int>(num);
       return 1;
 
     case BIO_CTRL_WPENDING: