Add missing revert() in OPCPackage to close Zip-streams always

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1850115 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/openxml4j/opc/OPCPackage.java

@@ -455,6 +455,9 @@ public abstract class OPCPackage implements RelationshipSource, Closeable {
 			output.close();
 		}
 
+		// ensure all held resources are freed
+        revert();
+
 		// Clear
 		this.contentTypeManager.clearAll();
 	}