Fix error building from teamcity

Change-Id: I1a4e1005bcb7181fd038b73829d77090031ed252
Reviewed-on: http://gerrit.dmdirc.com/2501
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager

build-ivy.xml

@@ -34,6 +34,7 @@
             </path>
             <map from="${basedir}${file.separator}" to=""/>
         </pathconvert>
+        <touch file="nbproject/private/private.properties"/>
         <propertyfile file="nbproject/private/private.properties">
             <entry operation="=" key="lib.classpath" value="${lib.classpath.computed}"/>
         </propertyfile>