Gracefully handle the error case of no job being created

CCBUG: 278252

shell/projectsourcepage.cpp

@@ -132,7 +132,6 @@ VcsJob* ProjectSourcePage::jobPerCurrent()
     } else if(m_providerWidget) {
         job=m_providerWidget->createWorkingCopy(url);
     }
-    Q_ASSERT(job);
     return job;
 }
 
@@ -149,6 +148,9 @@ void ProjectSourcePage::getVcsProject()
     }
     
     VcsJob* job=jobPerCurrent();
+    if (!job) {
+        return;
+    }
     
     m_ui->sources->setEnabled(false);
     m_ui->sourceBox->setEnabled(false);