Fix bgo #720443 (Lilith Bryant)

	* libbalsa/rfc3156.c (libbalsa_body_decrypt): trivial patch
	to fix the OL pk7 S/MIME issue.
Fix different handling of crypto icons

	* libbalsa/rfc3156.c (libbalsa_body_decrypt): tree view icons
	were handled differently for GPG and S/MIME.