Stop installcleaning $PRODUCT_OUT/*.{ini,txt,xlb}

For *.ini/*.txt files we should be recreating them as the instructions
change, so we shouldn't need to remove them. The biggest reason to
remove them is that the auto-installclean was removing
$PRODUCT_OUT/build_fingerprint.txt just after Kati wrote it out, causing
the fingerprint to be blank on builds where the auto installclean code
ran.

There's no reference to xlb in our tree, and it's been around since the
beginning of git history, so remove it.

Bug: 62224537
Test: lunch aosp_arm-eng; m nothing;
      lunch aosp_arm-userdebug; m -j nothing;
      check out/target/product/generic/build_fingerprint.txt
Change-Id: Id391af5c7d95ea78e4e68fae294d8295fccb1964

ui/build/cleanbuild.go

@@ -95,9 +95,6 @@ func installClean(ctx Context, config Config, what int) {
 		hostOut("testcases"),
 		hostOut("vts"),
 		productOut("*.img"),
-		productOut("*.ini"),
-		productOut("*.txt"),
-		productOut("*.xlb"),
 		productOut("*.zip"),
 		productOut("kernel"),
 		productOut("data"),