title: change rpmbuild directory to /var/lib/jenkins/rpmbuild/
body: <p>I am generating an RPM package using jenkins, although SOURCE, BUILD, BUILDROOT are all stored under /var/lib/jenkins/rpmbuild/, the rpm package after generation gets redirected to /root/rpmbuild/RPMS and I get error as</p>
  
  <pre><code>error: cannot create /root/rpmbuild/RPMS/noarch: Permission denied
  </code></pre>
  
  <p>I tried creating /var/lib/jenkins/rpmbuild/RPMS/noarch but it failed, I checked my .rpmmacro too and there I have defined topdir as</p>
  
  <pre><code>%_topdir %(echo $HOME)/rpmbuild
  </code></pre>
  
  <p>and owner and group of .rpmmacro is jenkins</p>
  
  <p>I want the rpm package to get stored under /var/lib/jenkins/rpmbuild/RPMS/noarch/ as the task is build by jenkins and that's the only directory that jenkins owns.</p>