allow compilation without opencv
allow compilation without opencv

amplab/SparkNet,rahulbhalerao001/SparkNet,amplab/SparkNet,rahulbhalerao001/SparkNet,rahulbhalerao001/SparkNet,rahulbhalerao001/SparkNet,amplab/SparkNet,rahulbhalerao001/SparkNet,rahulbhalerao001/SparkNet,rahulbhalerao001/SparkNet