crypto/x509: add /etc/ssl/cacert.pem to OmniOS cert search list

Fixes #9146.

Change-Id: If5cb5ae92a201825b9ff32b3d0edfa032b9a0965
Reviewed-on: https://go-review.googlesource.com/12203
Reviewed-by: Andrew Gerrand <adg@golang.org>

src/crypto/x509/root_solaris.go

@@ -8,4 +8,5 @@ package x509
 var certFiles = []string{
 	"/etc/certs/ca-certificates.crt",     // Solaris 11.2+
 	"/etc/ssl/certs/ca-certificates.crt", // Joyent SmartOS
+	"/etc/ssl/cacert.pem",                // OmniOS
 }