doc: cleaup extensions.d instructions
doc: cleaup extensions.d instructions

Change-Id: I17fd8a78071730bab09ce344b7138cd1e40abe68
Signed-off-by: Alon Bar-Lev <2e3ceb4d37adc6ae3ccc00d3646e0e0a036ace03@redhat.com>

alonbl/ovirt-engine-extension-aaa-ldap,oVirt/ovirt-engine-extension-aaa-ldap,oVirt/ovirt-engine-extension-aaa-ldap,alonbl/ovirt-engine-extension-aaa-ldap,alonbl/ovirt-engine-extension-aaa-ldap,oVirt/ovirt-engine-extension-aaa-ldap