try to standardize environment variable name

module/frontend/svscan@

@@ -13,15 +13,16 @@
 @execute = (
     s6-setsid -qb --
     umask 022
-    execl-cmdline -s { 66 ${main_args} scandir start ${scandir_args} }
+    execl-cmdline -s { 66 ${Args66} scandir ${ArgsScandirStart} }
 )
 
 [stop]
 @runas = @I
 @execute = (
-    execl-cmdline -s { 66 ${main_args} scandir stop }
+    execl-cmdline -s { 66 ${Args66} scandir ${ArgsScandirStop} }
 )
 
 [environment]
-main_args=!@verbosity_level@ @live_dir@
-scandir_args=!@notify@ @use_environment@
+Args66=!@verbosity_level@ @live_dir@
+ArgsScandirStart=!start @notify@ @use_environment@
+ArgsScandirStop=!stop