Currently when running the 'nbm' target in a module build script, if you do not
wish to sign the NBM (e.g. because you do not have the secret key) you must know
to pass -Dstorepass=\? to suppress signing which is not obvious. (The MakeNBM
task recognizes this password specially as meaning "do not try to sign the
NBM".)

Suggest that every build script with an 'nbm' target begin this target with a
default:

<target name="nbm" depends="netbeans">
    <property name="storepass" value="?"/>
    <makenbm ....>
</target>

Then module developers who simply type "ant -f mymodule/build.xml nbm" will get
an unsigned NBM, enough to test installation etc. If you pass the correct
keystore location and storage password, it will still be signed.

Also suggest nbbuild.netbeans.org web pages be updated to recommend this
property definition in the beginning of every 'nbm' target. Also the template
apisupport/src/org/netbeans/modules/apisupport/ant/AntScript.xml_ should be
updated to match.