Remove AndroidMkExtraFootersFunc entries param.

I added in case anyone needs to access AndroidMkEntries to generate
footer lines, but nobody uses it, and it only confuses people.

Test: m nothing, TreeHugger
Change-Id: Ic8a450e3c306d9228c1fdec212c7441bd6aaee03
diff --git a/java/robolectric.go b/java/robolectric.go
index 419efda..c821e5b 100644
--- a/java/robolectric.go
+++ b/java/robolectric.go
@@ -260,7 +260,7 @@
 	entries := &entriesList[0]
 
 	entries.ExtraFooters = []android.AndroidMkExtraFootersFunc{
-		func(w io.Writer, name, prefix, moduleDir string, entries *android.AndroidMkEntries) {
+		func(w io.Writer, name, prefix, moduleDir string) {
 			if s := r.robolectricProperties.Test_options.Shards; s != nil && *s > 1 {
 				numShards := int(*s)
 				shardSize := (len(r.tests) + numShards - 1) / numShards