Fix unit tests

app/src/test/java/org/traccar/client/DatabaseHelperTest.java

@@ -15,7 +15,6 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 
 @RunWith(RobolectricTestRunner.class)
-@Config(constants = BuildConfig.class, sdk = 21)
 public class DatabaseHelperTest {
 
     @Test

app/src/test/java/org/traccar/client/ProtocolFormatterTest.java

@@ -13,7 +13,6 @@ import java.util.Date;
 import static org.junit.Assert.assertEquals;
 
 @RunWith(RobolectricTestRunner.class)
-@Config(constants = BuildConfig.class, sdk = 21)
 public class ProtocolFormatterTest {
 
     @Test

app/src/test/java/org/traccar/client/RequestManagerTest.java

@@ -10,7 +10,6 @@ import org.robolectric.annotation.Config;
 import static org.junit.Assert.assertTrue;
 
 @RunWith(RobolectricTestRunner.class)
-@Config(constants = BuildConfig.class, sdk = 21)
 public class RequestManagerTest {
 
     @Ignore