forgot to handle the -f option

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@13213 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/tasks/Maven.java

@@ -189,6 +189,8 @@ public class Maven extends Builder {
                 }
                 args.add(exec);
             }
+            if(pom!=null)
+                args.add("-f",pom);
             args.addKeyValuePairs("-D",build.getBuildVariables());
             args.addKeyValuePairsFromPropertyString("-D",properties,vr);
             args.addTokenized(normalizedTarget);