Fix versioning on about.ipxe

roles/netbootxyz/templates/menu/about.ipxe.j2

@@ -16,7 +16,7 @@ set fg_cya ${esc:string}[36m
 set fg_whi ${esc:string}[37m
 
 :netabout
-menu ${fg_cya}${bold}About netboot.xyz (Version: ${boot_version})
+menu ${fg_cya}${bold}About netboot.xyz (Version: ${version})
 item exit ${bold}Exit back to main menu...${boldoff}
 item --gap --  --------------------------------------------------------------------------
 item about ${fg_gre}${bold}Self Hosting and Live Booting - November 29, 2019
@@ -35,7 +35,7 @@ item about ${fg_gre}${bold}Sponsorship: ${fg_whi}${bold}https://opencollective.c
 item --gap --  --------------------------------------------------------------------------
 isset ${upstream_version} && goto display_version || goto skip_version
 :display_version
-iseq ${boot_version} ${upstream_version} || item --gap --  ${fg_gre}${bold}Latest netboot.xyz version available: ${fg_whi}${bold}${upstream_version}
+iseq ${version} ${upstream_version} || item --gap --  ${fg_gre}${bold}Latest netboot.xyz version available: ${fg_whi}${bold}${upstream_version}
 item --gap --  --------------------------------------------------------------------------
 :skip_version
 choose selected || goto exit