following up tweaks to the previous commit, and explaining what we don't do so...

following up tweaks to the previous commit, and explaining what we don't do so that future versions don't inadvertently mess up them

debian/debian/jenkins.postinst

@@ -42,8 +42,10 @@ case "$1" in
         fi
       
         # directories needed for jenkins
-        chown -R jenkins:adm /var/lib/jenkins /var/log/jenkins
-        #chmod 750         /var/lib/jenkins /var/log/jenkins
+        # we don't do -R because it can take a long time on big installation
+        chown jenkins:adm /var/lib/jenkins /var/log/jenkins
+        # we don't do "chmod 750" so that the user can choose the pemission for g and o on their own
+        chmod u+rwx /var/lib/jenkins /var/log/jenkins
 
         # make sure jenkins can delete everything in /var/run/jenkins to re-explode war
         chown -R jenkins:adm /var/run/jenkins