calcurse-upgrade: Change location of temporary file
calcurse-upgrade: Change location of temporary file

Instead of creating the temporary file in a central location, place it
in the same directory as the configuration file. Pros:

* No need to rely on the "$TMPDIR" environment variable.

* Multiple users can upgrade their configuration files at the same time,
  even if "$!" isn't set properly.

* One user can upgrade several configuration files (in different
  directories or with different file names) at once.

Signed-off-by: Lukas Fleischer <af90e31281d8305af43dc616c5aaca3c7165f8a7@cryptocrack.de>

lfos/calcurse,lfos/calcurse,lfos/calcurse