Fix NullPointerException during branch indexing

The "properties" element is not optional. It also can't be an empty
list, due to an apparent bug in jenkins job builder.

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
Change-Id: Ia671a271f3d6c4c581de1251c9aae0e3d028cb37
1 file changed