Extensions can be created with same number as some featurcodes

[Stell0]

Steps to reproduce

• from wizard, try to create 555 extension

Expected behavior

• 555 is a default featurecode and should be denied to create an extension with this number

Actual behavior

Extension is created

[nethbot]

in 7.9.2009/nethesis-testing:

• nethvoice-wizard-restapi-14.16.2-1.1.g48c205d.ns7.noarch.rpm x86_64

[nethbot]

in 7.9.2009/nethesis-updates:

• nethvoice-wizard-restapi-14.16.3-1.ns7.noarch.rpm x86_64