have pkgman create the directories it needs rather than fail for cryptic reasons

lib/pkgman.lua

@@ -7,6 +7,8 @@ pkg.sourcePath = pkg.cfgPath .. "/sources.cfg"
 pkg.installedPath = pkg.cfgPath .. "/installed.cfg"
 local w, lz16 = pcall(require,"liblz16")
 if not w then lz16 = nil end
+fs.makeDirectory("/boot/pkg")
+fs.makeDirectory("/boot/cfg/pkg")
 require "pkgfs"
 
 local function getSources()