Fix Kindle FW detection (#4336)

* Fix version comparisons...

frontend/device/kindle/device.lua

@@ -131,6 +131,8 @@ function Kindle:outofScreenSaver()
             end
         end
         local UIManager = require("ui/uimanager")
+        -- NOTE: If we *really* wanted to avoid the framework seeping through, we could use tickAfterNext instead,
+        --       at the cost of an extra flashing update...
         UIManager:nextTick(function() UIManager:setDirty("all", "full") end)
     end
     self.powerd:afterResume()

platform/kindle/koreader.sh

@@ -185,7 +185,7 @@ fi
 
 # Normalize a version string for easy numeric comparisons
 # c.f., https://stackoverflow.com/a/37939589
-version() { echo "$@" | awk -F. '{ printf("%d%03d%03d%03d\n", $1,$2,$3,$4); }'; }
+version() { echo "$@" | awk -F. '{ printf("%d%03d%03d\n", $1,$2,$3); }'; }
 
 # check if kpvbooklet was launched more than once, if not we will disable pillow
 # there's no pillow if we stopped the framework, and it's only there on systems with upstart anyway