Removed caching from native code

bindings/java/jni/auto_db_java.cpp

bindings/java/jni/auto_db_java.h

bindings/java/src/org/sleuthkit/datamodel/JniDbHelper.java

bindings/java/src/org/sleuthkit/datamodel/SleuthkitCase.java

bindings/java/src/org/sleuthkit/datamodel/SleuthkitJNI.java