external/boringssl: bump revision.

This change bumps the BoringSSL revision to the current tip-of-tree.

Change-Id: I91d5bf467e16e8d86cb19a4de873985f524e5faa
diff --git a/src/crypto/sha/sha1.c b/src/crypto/sha/sha1.c
index 7595bc8..60d09f6 100644
--- a/src/crypto/sha/sha1.c
+++ b/src/crypto/sha/sha1.c
@@ -367,8 +367,9 @@
     c->h3 = (c->h3 + B) & 0xffffffffL;
     c->h4 = (c->h4 + C) & 0xffffffffL;
 
-    if (--num == 0)
+    if (--num == 0) {
       break;
+    }
 
     A = c->h0;
     B = c->h1;