Fixed '[pt.webdetails.cda.CdaContentGenerator] doQuery: Cannot process n...

If one of tables under join return empty result, here's the exception that's thrown to the log:

2013-11-14 10:53:27,060 ERROR [pt.webdetails.cda.CdaContentGenerator] doQuery: Cannot process null table.
java.lang.IllegalArgumentException: Cannot process null table.
        at pt.webdetails.cda.utils.TableModelUtils.postProcessTableModel(TableModelUtils.java:81)
        at pt.webdetails.cda.dataaccess.AbstractDataAccess.doQuery(AbstractDataAccess.java:276)
        at pt.webdetails.cda.CdaEngine.doQuery(CdaEngine.java:86)
        at pt.webdetails.cda.CdaCoreService.doQuery(CdaCoreService.java:196)
        at pt.webdetails.cda.CdaContentGenerator.doQuery(CdaContentGenerator.java:107)
        at sun.reflect.GeneratedMethodAccessor130.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at pt.webdetails.cpf.SimpleContentGenerator.invokeMethod(SimpleContentGenerator.java:334)
        at pt.webdetails.cpf.SimpleContentGenerator.createContent(SimpleContentGenerator.java:168)
        at sun.reflect.GeneratedMethodAccessor129.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.pentaho.platform.web.http.context.WebSpringPentahoObjectFactory$a.invoke(SourceFile:288)
        at com.sun.proxy.$Proxy19.createContent(Unknown Source)
        at org.pentaho.platform.web.servlet.GenericServlet.doGet(GenericServlet.java:261)
        at org.pentaho.platform.web.servlet.GenericServlet.doPost(GenericServlet.java:80)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.pentaho.platform.web.http.filters.PentahoWebContextFilter.doFilter(PentahoWebContextFilter.java:142)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.pentaho.platform.web.http.filters.PentahoRequestContextFilter.doFilter(PentahoRequestContextFilter.java:84)