Exit with non-zero status when db:drop fails

* If the drop task fails for a reason other than the database not
  existing, processing should end. This is indicated by a non-zero
  exit status.
* Since the backtrace is already printed to screen, we forgo
  printing it again by using an explicit call to `exit`.
* ⚠ This modifies the behavior of the db:create task slightly in
  that the stack trace is no longer printed by default. If the `--trace`
  option is used, it will print the trace _after_ the error message.

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -116,8 +116,9 @@ def drop(*arguments)
       rescue ActiveRecord::NoDatabaseError
         $stderr.puts "Database '#{configuration['database']}' does not exist"
       rescue Exception => error
-        $stderr.puts error, *(error.backtrace)
+        $stderr.puts error
         $stderr.puts "Couldn't drop #{configuration['database']}"
+        raise
       end
 
       def drop_all

railties/test/application/rake/dbs_test.rb

@@ -91,6 +91,16 @@ def with_bad_permissions
         end
       end
 
+      test 'db:drop failure because bad permissions' do
+        with_database_existing do
+          with_bad_permissions do
+            output = `bin/rake db:drop 2>&1`
+            assert_match /Couldn't drop/, output
+            assert_equal 1, $?.exitstatus
+          end
+        end
+      end
+
       def db_migrate_and_status(expected_database)
         Dir.chdir(app_path) do
           `bin/rails generate model book title:string;