Make CopyOf generic

Test: util_test.go
Change-Id: If8f2534ec454903eb967dc9ec0c8708096d1baff
diff --git a/android/util_test.go b/android/util_test.go
index bee31a9..0e28b56 100644
--- a/android/util_test.go
+++ b/android/util_test.go
@@ -385,7 +385,7 @@
 	emptyList := []string{}
 	copyOfEmptyList := CopyOf(emptyList)
 	AssertBoolEquals(t, "Copy of an empty list should be an empty list and not nil", true, copyOfEmptyList != nil)
-	copyOfNilList := CopyOf(nil)
+	copyOfNilList := CopyOf([]string(nil))
 	AssertBoolEquals(t, "Copy of a nil list should be a nil list and not an empty list", true, copyOfNilList == nil)
 }