Fixes #3842: correct save button activation
Fixes #3861: Get the full group category entry to check its class

Also correct two reporting error and comments
Merge pull request #309 from fanf/bug_3861/ldap_error_when_deleting_category

Fixes #3861: Get the full group category entry to check its class
Merging 2.4 into 2.6
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7
Merge pull request #308 from ncharles/bug_3842/dev/correct_save_button

Bug 3842/dev/correct save button
Merge branch 'branches/rudder/2.4' into branches/rudder/2.6

Conflicts:
	rudder-web/src/main/scala/com/normation/rudder/web/components/NodeGroupForm.scala
	rudder-web/src/main/webapp/javascript/rudder/rudder.js
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7
Merge branch 'branches/rudder/2.7'