test db existence on the remote host

Summary:
Fix the bug that previous test existence locally
Closes https://github.com/facebook/rocksdb/pull/2074

Differential Revision: D4813631

Pulled By: lightmark

fbshipit-source-id: eceb0d9

tools/regression_test.sh

@@ -126,13 +126,11 @@ function main {
   if [ $TEST_MODE -le 1 ]; then
       tmp=$DB_PATH
       DB_PATH=$ORIGIN_PATH
-      if [ ! -e $DB_PATH ]; then
+      run_remote "test -d $DB_PATH"
+      if [[ $? -ne 0 ]] || [[ $(run_remote 'echo $(( $(date +"%s") - $(stat -c "%Y" '"$a"') ))') -gt "604800" ]]; then
+          rm -rf "$DB_PATH"
           echo "Building DB..."
           run_db_bench "fillseqdeterministic" $NUM_KEYS 1 0
-      elif [[ ! -d $DB_PATH ]] || [[ "$(( $(date +"%s") - $(stat -c "%Y" $DB_PATH) ))" -gt "604800"  ]]; then
-          echo "Rebuilding DB..."
-          rm -rf $DB_PATH
-          run_db_bench "fillseqdeterministic" $NUM_KEYS 1 0
       fi
       DB_PATH=$tmp
   fi