Close session after provisioning

Merge of CDM change:
https://widevine-internal-review.googlesource.com/#/c/10691/

This prevents the provisioning session from being created unless the
device needs provisioning.  And then, after provisioning, it closes
the session it had previously opened.

b/15782159 CertificateProvisioning object keeps unused CryptoSession

Change-Id: Ic52ed864fa47c7ba50b7ca4d9fea1e74930228e9

libwvdrmengine/cdm/core/src/crypto_session.cpp

@@ -7,6 +7,7 @@
 
 #include <arpa/inet.h>  // needed for ntoh()
 #include <iostream>
+#include <string.h>
 
 #include "crypto_key.h"
 #include "log.h"