Fixed boot script (no updated /local/examid)

bin-ubuntu/get-config

@@ -266,13 +266,13 @@ start() {
                 # if the exam is already started, get examid from file
                 if [[ -f /local/examid ]]; then
                     EXAM_ID_PREV=`cat /local/examid`
-                # otherwise let's create the file with the current examid
-                else
-                    echo "${EXAM_ID}" > /local/examid
                 fi
 
                 # different examid?
                 if [[ ${EXAM_ID} != ${EXAM_ID_PREV} ]]; then
+                    # update the file with the current examid
+                    echo "${EXAM_ID}" > /local/examid
+                    # clean home dir if requested by the profile
                     touch /local/mk-homedir
                 fi
             fi