main: Run registerGlobalConfig before loading config

This is a bit of a trip.

Commit 63b0a01d75 moved config
initialization out of static initializers.

In doing so, an oversight was made with the new
`GlobalConfig::registerGlobalConfig` calls. Previously all global
configuration would be handled well before `loadConfFile` was called.

The change placed `registerGlobalConfig` in `main` *after*
`initNix`. The `initNix` function is what calls `initLibStore`, which in
turn callse `loadConfFile`.

So, in effect, the configuration for `daemonAuthorizationSettings` and
`nixDevelopSettings` are not actually loaded.

Change-Id: I10dba2c98e032f910942ee0e0ca6bb39ef60edc2

lix/nix/main.cc

@@ -458,12 +458,12 @@ int mainWrapped(AsyncIoRoot & aio, int argc, char ** argv)
         return 0;
     }
 
-    initNix();
-    initLibExpr();
-
     GlobalConfig::registerGlobalConfig(daemonAuthorizationSettings);
     GlobalConfig::registerGlobalConfig(nixDevelopSettings);
 
+    initNix();
+    initLibExpr();
+
 #if __linux__
     if (getuid() == 0) {
         try {