Remove first argument of Schema::isModule

The argument wasn't used anywhere, I have no idea why it was there.

Change-Id: I21b9c3fa323187e5f0484d4db9e2c543f9a6f7cf
diff --git a/src/yang_schema.cpp b/src/yang_schema.cpp
index 89c515d..9868c63 100644
--- a/src/yang_schema.cpp
+++ b/src/yang_schema.cpp
@@ -81,7 +81,7 @@
     }
 }
 
-bool YangSchema::isModule(const schemaPath_&, const std::string& name) const
+bool YangSchema::isModule(const std::string& name) const
 {
     const auto set = modules();
     return set.find(name) != set.end();