Pull Request for Issue # .

Summary of Changes

This PR cleans up Captcha usage.

When Captcha plugin is set in Global or Component configuration, disabling, uninstalling or changing access level of the plugin causes system messages and fatal errors. Generally, plugin status should not cause such issues.

Testing Instructions

Enable and configure a Captcha plugin.
Select the plugin in Global Configuration and in component (com_content and com_contact) options.
Disable or uninstall the plugin.

a) Enter username reminder or password reset view in Users component.
b) Submit the form in one of the above views.
c) Submit Contact form.
d) Submit Article from frontend.
e) Now enable the plugin (or install and enable if it was uninstalled) and repeat the above scenarios.

Expected result

a) No errors. Captcha is not shown in form.
b, c, d) Forms successfully submitted.
e) Works like before patch.

Actual result

a) System message:

Error
Captcha plugin not set or not found. Please contact a site administrator.

Captcha field label is shown in form.

b, c, d)
Submitting form causes error:

Error
Call to a member function checkAnswer() on null

e) Works like before patch.

Documentation Changes Required

No.