unit-test: add valijson

Add the valijson package, used by entity-manager.  entity-manager is
able to pass CI today with vendoring.  This patch removes the need for
vendoring.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: Icc3a6567dfb31f04cdbed1f5061dd89d21dc0275
1 file changed