Disable auto-magic 'mvn exec' for now

It interferes with the way this developer wants to combine annotations.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fixup! TEMP: Use scijava-common 2.6.0
app/pom.xml: execute CombineAnnotations in the 'deps' profile

This accumulates all the annotation indexes and writes them into
target/assembly/all/.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fixup! Aggregate json annotations in uber-jar