rust: fully disable all lints when no_lint is set

If the no_lint attribute is set, we now explicitly disable any warning
or error.

Bug: 162897623
Test: cd external/selinux; mma; check the build log for warnings
Change-Id: I5338bda77ab25ded7cc43cc3afd29419fcbd9808
diff --git a/rust/config/lints.go b/rust/config/lints.go
index 529d094..e24ffac 100644
--- a/rust/config/lints.go
+++ b/rust/config/lints.go
@@ -128,6 +128,7 @@
 	{"vendor/google", rustcDefault, true, clippyDefault},
 	{"vendor/", rustcVendor, true, clippyVendor},
 }
+var AllowAllLints = rustcAllowAll
 
 // ClippyLintsForDir returns a boolean if Clippy should be executed and if so, the lints to be used.
 func ClippyLintsForDir(dir string) (bool, string) {