Connection manager, add connection with empty string error

[Cecilia Vela Gurovic]

In screen webservice/admin/connections.php
when trying to add a connection with an empty string an error "Mahara: Site unavailable" is displayed

with warnings

[WAR] c9 (webservice/admin/addconnection.php:32) Undefined offset: 1
Call stack (most recent first):

    log_message("Undefined offset: 1", 8, true, true, "/home/ceciliavg/maharacode/mahara/htdocs/webservic...", 32) at /home/ceciliavg/maharacode/mahara/htdocs/lib/errors.php:521
    error(8, "Undefined offset: 1", "/home/ceciliavg/maharacode/mahara/htdocs/webservic...", 32, array(size 64)) at /home/ceciliavg/maharacode/mahara/htdocs/webservice/admin/addconnection.php:32

[WAR] c9 (webservice/admin/addconnection.php:32) Undefined offset: 2
Call stack (most recent first):

    log_message("Undefined offset: 2", 8, true, true, "/home/ceciliavg/maharacode/mahara/htdocs/webservic...", 32) at /home/ceciliavg/maharacode/mahara/htdocs/lib/errors.php:521
    error(8, "Undefined offset: 2", "/home/ceciliavg/maharacode/mahara/htdocs/webservic...", 32, array(size 64)) at /home/ceciliavg/maharacode/mahara/htdocs/webservice/admin/addconnection.php:32

[WAR] c9 (lib/mahara.php:1511) "" is not a valid plugin type
Call stack (most recent first):

    safe_require("", "") at /home/ceciliavg/maharacode/mahara/htdocs/webservice/admin/addconnection.php:59

[Mahara Bot (dev-mahara)]

Patch for "master" branch: https://reviews.mahara.org/7363

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/7363
Committed: https://git.mahara.org/mahara/mahara/commit/b97aa531c0812e6ac8bc4dc9f100b9b5b775ca78
Submitter: Robert Lyon (<email address hidden>)
Branch: master

commit b97aa531c0812e6ac8bc4dc9f100b9b5b775ca78
Author: Cecilia Vela Gurovic <email address hidden>
Date: Fri Dec 23 09:11:12 2016 +1300

Bug 1648636: Error message fix, connection manager

Fix for error when trying to add a connection with an
empty string.
Select and add button should not be displayed when
there are no client connections for the institution.

behatnotneeded

Change-Id: Ib90511512c91941b59bef0df19fedd3810fc0fc6