Add NPE check when masking Wi-Fi configuration

Add another safety check.

Bug: 141328297
Test: atest com.android.server.wifi
Change-Id: I2b6845264757b0908ecf389f46d83dc1c2e249dc
1 file changed
tree: 05b17b24004e48bb64fddb640f8c895c3961324d
  1. service/
  2. PREUPLOAD.cfg