Re-exec startup script on Kindle/Kobo when an OTA update is processed on startup (#4062)

So that we may properly pickup potential updates to the startup script
itself.

platform/kobo/koreader.sh

@@ -28,8 +28,13 @@ ko_update_check() {
         rm -f "${NEWUPDATE}" # always purge newupdate in all cases to prevent update loop
     fi
 }
-# NOTE: Keep doing an initial update check, in addition to one during the restart loop...
+# NOTE: Keep doing an initial update check, in addition to one during the restart loop, so we can pickup potential updates of this very script...
 ko_update_check
+# If an update happened, and was successful, reexec
+if [ -n "${fail}" ] && [ "${fail}" -eq 0 ]; then
+    # By now, we know we're in the right directory, and our script name is pretty much set in stone, so we can forgo using $0
+    exec ./koreader.sh "${@}"
+fi
 
 # load our own shared libraries if possible
 export LD_LIBRARY_PATH="${KOREADER_DIR}/libs:${LD_LIBRARY_PATH}"