Changeset I49255255 has added an 'is_base' attribute for Image Schema
properties, thus allowing to differentiate between base and custom image
properties, but the client hasn't make any use of it.
This patch adds appropriate attribute to SchemaProperty class and a
helper method which allows to validate if the given property is base or
not.
The added helper method (is_base_property) should not be confused with
the existing is_core_property: the latter just checks if the property is
known to the schema, regardless of its being base or not.
Change-Id: I7c397196dad9ae5494ed2f8f3aacef3fc1ce70d8
Partial-Bug: #1323660
Alexander Tivelkov
90407d9e47