Not possible. You could
1. Disable updates completely (setting in xpam.ini). Enable if there is some important update, right now nothing planned really.
2. Make an empty file and rename it to DotA_Allstars_7.00e6.w3x .. this will trick the updater into thinking you already have the map. Or.. it should in theory, did not test it.
e4 is also an update now but I will remove that.