Don't compare hashes if pull failed

Also fix minor style nit.

bin/homeshick

@@ -171,7 +171,7 @@ case $cmd in
   cd)    help cd        ;; # cd is implemented in the homeshick.{sh,csh} helper script.
   help)  help $help_cmd ;;
   *)
-    declare -a pull_completed
+    pull_completed=()
     for param in "${params[@]}"; do
       case $cmd in
         clone)
@@ -183,11 +183,13 @@ case $cmd in
         refresh)
           (refresh $threshhold "$param") ;;
         pull)
-          prev_hash=$(cd "$repos/$param" && git rev-parse HEAD)
+          prev_hash=$(cd "$repos/$param" && git rev-parse HEAD --)
           (pull "$param")
           result=$?
-          curr_hash=$(cd "$repos/$param" && git rev-parse HEAD)
-          [[ "$prev_hash" != "$curr_hash" ]] && pull_completed+=("$param")
+          if [[ $result -eq 0 ]]; then
+            curr_hash=$(cd "$repos/$param" && git rev-parse HEAD --)
+            [[ "$prev_hash" != "$curr_hash" ]] && pull_completed+=("$param")
+          fi
           (exit $result)
           ;;
         symlink|link)