Shared lib dependencies from rlib are included in APEX

This change fixes a bug that shared lib dependencies of an rlib is not
installed to the APEX even when the rlib is part of the APEX.

Bug: N/A
Test: m
Change-Id: I88fe461584499839d8018d6b4292374592e7562b
diff --git a/rust/rust.go b/rust/rust.go
index 566ad37..34e197a 100644
--- a/rust/rust.go
+++ b/rust/rust.go
@@ -798,6 +798,11 @@
 	return ok && tag == dylibDepTag
 }
 
+func IsRlibDepTag(depTag blueprint.DependencyTag) bool {
+	tag, ok := depTag.(dependencyTag)
+	return ok && tag == rlibDepTag
+}
+
 type autoDep struct {
 	variation string
 	depTag    dependencyTag