Bug#981927: ant: Disable doclint by default to reduce the build failures with OpenJDK 17

[Emmanuel Bourg]

Package: ant
Version: 1.10.9-2
Severity: important
User: debian-java at lists.debian.org
Usertags: default-java17

Several packages fail to build with OpenJDK 17 because the javadoc linter is
too strict. When building a Debian package ant should automatically disable
doclint (similarly to the --ignore-source-errors option already added when
running the javadoc task).