fix: show N/A if env version unknown

See toolshed/abra#478

tests/integration/app_rollback_overview.bats

@@ -19,6 +19,7 @@ setup(){
 }
 
 teardown(){
+  _reset_app
   _undeploy_app
   _reset_recipe
 }
@@ -74,3 +75,30 @@ teardown(){
     "$ABRA_DIR/servers/$TEST_SERVER/$TEST_APP_DOMAIN.env"
   assert_success
 }
+
+@test "app rollback no .env version" {
+  run $ABRA app deploy "$TEST_APP_DOMAIN" "0.2.0+1.21.0" \
+    --no-input --no-converge-checks
+  assert_success
+
+  _wipe_env_version
+
+  run $ABRA app rollback "$TEST_APP_DOMAIN" "0.1.0+1.20.0" \
+    --no-input --no-converge-checks
+  assert_success
+
+  # current deployment
+  assert_output --regexp 'VERSION.*' + "0.2.0+1.21.0"
+  assert_output --regexp 'CHAOS.*false'
+
+  # rollback
+  assert_output --regexp 'VERSION.*' + "0.1.0+1.20.0"
+
+  # env version
+  assert_output --regexp 'CURRENT VERSION.*N/A'
+  assert_output --regexp 'NEW VERSION.*' + "0.2.0+1.21.0"
+
+  run grep -q "TYPE=$TEST_RECIPE:${latestRelease}" \
+    "$ABRA_DIR/servers/$TEST_SERVER/$TEST_APP_DOMAIN.env"
+  assert_success
+}