crypto/x509: add /etc/ssl/certs to certificate directories

Fixes #12139.

Change-Id: Ied760ac37e2fc21ef951ae872136dc3bfd49bf9f
Reviewed-on: https://go-review.googlesource.com/16671Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/crypto/x509/root_unix.go

@@ -11,6 +11,7 @@ import "io/ioutil"
 // Possible directories with certificate files; stop after successfully
 // reading at least one file from a directory.
 var certDirectories = []string{
+	"/etc/ssl/certs",               // SLES10/SLES11, https://golang.org/issue/12139
 	"/system/etc/security/cacerts", // Android
 }