Update CertificateManager.java 

	Resolve exception：
                org.jivesoftware.util.CertificateManager - Error decoding subjectAltName
		java.lang.ClassCastException: org.bouncycastle.asn1.DERTaggedObject
		cannot be cast to org.bouncycastle.asn1.ASN1Sequence

       Hope this is right, I'm just learning to use git, thanks guys