Ignore non-empty directories in cleanup file

- Before ruby 2.5, FileUtils.rmdir silently fails when the target
directory is not empty, so the non-empty directories in cleanup file
are not removed. But the implementation of rmdir is changed in
ruby 2.5 so that it doesn’t rescue Errno::ENOTEMPTY any more.

lib/instance_agent/plugins/codedeploy/install_instruction.rb

@@ -209,10 +209,10 @@ def execute
             FileUtils.rm(@file_path)
           elsif File.exist?(@file_path)
             if File.directory?(@file_path)
-              # TODO (AWSGLUE-713): handle the exception if the directory is non-empty;
-              # this might mean the customer has put files in this directory and we should
-              # probably ignore the error and move on
-              FileUtils.rmdir(@file_path)
+              begin
+                FileUtils.rmdir(@file_path)
+              rescue Errno::ENOTEMPTY
+              end
             else
               FileUtils.rm(@file_path)
             end

test/instance_agent/plugins/codedeploy/install_instruction_test.rb

@@ -249,14 +249,34 @@ class InstallInstructionTest < InstanceAgentTestCase
               File.stubs(:exist?).with("test_delete_path").returns(true)
             end
 
-            should "produce a command that deletes test_delete_path" do
+            should "use rm for a regular file" do
               commands = InstallInstruction.parse_remove_commands(@parse_string)
               FileUtils.expects(:rm).with("test_delete_path")
-              assert_not_equal nil, commands
               commands.each do |command|
                 command.execute
               end
             end
+
+            should "use rmdir for a directory" do
+              File.stubs(:directory?).with("test_delete_path").returns(true)
+              commands = InstallInstruction.parse_remove_commands(@parse_string)
+              FileUtils.expects(:rmdir).with("test_delete_path")
+              commands.each do |command|
+                command.execute
+              end
+            end
+
+            should "ignore a non-empty directory by rescuing Errno::ENOTEMPTY" do
+              File.stubs(:directory?).with("test_delete_path").returns(true)
+              commands = InstallInstruction.parse_remove_commands(@parse_string)
+              FileUtils.stubs(:rmdir).raises(Errno::ENOTEMPTY)
+
+              assert_nothing_raised do
+                commands.each do |command|
+                  command.execute
+                end
+              end
+            end
           end
 
           context "multiple files to delete" do