bump-pom-scijava: add ij1-patcher.version to the default properties

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
bump-pom-scijava: fix --deploy-only

We really need to switch to the correct directory in case we want to
deploy pom-scijava, even if it has been bumped manually.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>