[#1856] node: Fix config rereading

Config was reread from the file only once in two SIGHUPs.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

cmd/neofs-node/config.go

@@ -164,13 +164,10 @@ func (a *applicationConfiguration) readConfig(c *config.Config) error {
 
 		// clear if it is rereading
 		*a = applicationConfiguration{}
-	} else {
-		// update the status.
-		// initial configuration validation is expected to be
-		// performed on the higher level
-		a._read = true
 	}
 
+	a._read = true
+
 	a.EngineCfg.errorThreshold = engineconfig.ShardErrorThreshold(c)
 	a.EngineCfg.shardPoolSize = engineconfig.ShardPoolSize(c)