Changing the switch's text to yes/no for delete logo (Bug #1442150)

To make the switch button's function more logical.

Change-Id: Ia7714a50c91d7cbf0d9c9c64745b52be62838340
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>

htdocs/admin/users/institutions.php

@@ -394,6 +394,7 @@ if ($institution || $add) {
         );
         $elements['deletelogo'] = array(
             'type'        => 'switchbox',
+            'switchtext'  => 'yesno',
             'title'       => get_string('deletelogo', 'admin'),
             'description' => get_string('deletelogodescription1', 'admin'),
         );

htdocs/lang/en.utf8/admin.php

@@ -893,7 +893,7 @@ $string['licensedefaultmandatory'] = 'If users are required to choose a license,
 $string['Logo'] = 'Logo';
 $string['logodescription'] = 'You can upload an image here that will be displayed to your institution\'s members in place of the standard header logo. For best results, this image should have the same dimensions as the site logo in your institution\'s theme. As each theme can have a different header height, no exact dimensions can be provided.';
 $string['deletelogo'] = 'Delete logo';
-$string['deletelogodescription1'] = 'If set to "On", revert to the standard header logo for your institution\'s theme.';
+$string['deletelogodescription1'] = 'If set to "Yes", revert to the standard header logo for your institution\'s theme.';
 $string['customtheme'] = 'Custom theme configuration';
 $string['customtheme.background'] = 'Background';
 $string['customtheme.backgroundfg'] = 'Text on background';