refactor: don't call init() method on the interface that doesn't have it.

This change is needed in order to simplify automated porting of tests.

Part of 1246

Author: php-coder

src/test/groovy/ru/mystamps/web/feature/image/LegacyDatabaseImagePersistenceStrategyTest.groovy

@@ -32,13 +32,15 @@ class LegacyDatabaseImagePersistenceStrategyTest extends Specification {
 	private ImagePersistenceStrategy strategy
 
 	def setup() {
-		strategy = new DatabaseImagePersistenceStrategy(
+		DatabaseImagePersistenceStrategy dbStrategy = new DatabaseImagePersistenceStrategy(
 			NOPLogger.NOP_LOGGER,
 			imageDataDao
 		)
 
 		// init() does nothing except logging but by invoking it we're improving code coverage
-		strategy.init()
+		dbStrategy.init()
+		
+		strategy = dbStrategy
 	}
 
 	//