Fix for silverstripe#1018 "'Export To CSV' for Reports not working"

The call to LeftAndMain::Link() was appending the Action as opposed to passing it as a parameter
This resulted in the double forward slash (/),

There is still possibly an unresolved issue with LeftAndMain::Link() about appending the slash at the end??

code/ReportAdmin.php

@@ -179,7 +179,7 @@ public function reportEditFormFor($id) {
 			unset($filteredCriteria[$notAParam]);
 		}
 
-		$formLink = $this->Link() . '/EditForm';
+		$formLink = $this->Link( 'EditForm' );
 		if($filteredCriteria) $formLink .= '?' . http_build_query($filteredCriteria);
 		$form->setFormAction($formLink);
 		$form->setTemplate('ReportAdminForm');