Resolve Meson issues

This commit includes fixes in the repo:

1. Moving experimental filesystem to filesystem
2. Errors that meson identified

Signed-off-by: Ratan Gupta <ratankgupta31@gmail.com>
Change-Id: I93c77c2a434275c4da3ca4549919eaa55b57f481
diff --git a/snmp_main.cpp b/snmp_main.cpp
index 4522a2a..0ae1eef 100644
--- a/snmp_main.cpp
+++ b/snmp_main.cpp
@@ -13,13 +13,13 @@
 {
     void operator()(sd_event* event) const
     {
-        event = sd_event_unref(event);
+        sd_event_unref(event);
     }
 };
 
 using EventPtr = std::unique_ptr<sd_event, EventDeleter>;
 
-int main(int argc, char* argv[])
+int main(int /*argc*/, char** /*argv[]*/)
 {
     using namespace phosphor::logging;