Added nullability check

cameraview/src/main/java/com/otaliastudios/cameraview/engine/Camera1Engine.java

@@ -160,6 +160,9 @@ public class Camera1Engine extends CameraBaseEngine implements
     }
 
     private boolean previewAspectRatioEqualsForModes() {
+        if (mCaptureSize == null) {
+            return false;
+        }
         Size prevModeSize = mCaptureSize;
         mCaptureSize = computeCaptureSize();