manager: remove unused interface

The manager doesn't use the interface being passed in, so remove it.

Change-Id: I1ebb07a7fa109d41a0a06772c5229b896f4352f3
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/test/test.cpp b/test/test.cpp
index e7058be..7be9c64 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -471,8 +471,8 @@
 
 int main()
 {
-    phosphor::inventory::manager::Manager mgr(
-        sdbusplus::bus::new_default(), MGR_SERVICE, MGR_ROOT, MGR_INTERFACE);
+    phosphor::inventory::manager::Manager mgr(sdbusplus::bus::new_default(),
+                                              MGR_SERVICE, MGR_ROOT);
     ExampleService d;
 
     auto f1 = [](auto mgr) { mgr->run(); };