[kube-runtime] fix runtime bug (#3776)

Runtime goes wrong when repeat execuate in same env. Fix such bug

src/kube-runtime/src/init

@@ -88,7 +88,7 @@ PAI_LOG_DIR=${PAI_WORK_DIR}/logs/${FC_POD_UID}
 
 # Move previous logs to another folder. Notice: exclude for init.log, new log will append to previous log file
 LOG_FILES=$(find $PAI_LOG_DIR -maxdepth 1 -type f ! -name "init.log")
-if [[ ! -z $LOG_FILES ]]; then
+if [[ ! -z "$LOG_FILES" ]]; then
   echo "[WARN] $PAI_LOG_DIR not empty, contains previous results"
   PRE_LOG_DIR=$PAI_LOG_DIR/prelog_$RANDOM
   while [[ -d $PRE_LOG_DIR ]]
@@ -100,7 +100,7 @@ if [[ ! -z $LOG_FILES ]]; then
 fi
 
 # Clean ${PAI_WORK_DIR} since it may contain last execution content. (rarely happen, but seen in real world)
-find ${PAI_WORK_DIR} -maxdepth 1 -type f -exec rm {} \;
+find ${PAI_WORK_DIR} -maxdepth 1 -mindepth 1 ! -name "logs" -exec rm -rf {} \;
 
 
 # Move all runtime sources to PAI_WORK_DIR