Fix earfcn deletion

* fix typo in arg index
* fix sign in error reporting
* add vty test
diff --git a/openbsc/tests/vty_test_runner.py b/openbsc/tests/vty_test_runner.py
index 143ba5d..7f64a80 100644
--- a/openbsc/tests/vty_test_runner.py
+++ b/openbsc/tests/vty_test_runner.py
@@ -231,6 +231,20 @@
 
         self.assertEquals(self.vty.node(), 'config-mncc-int')
 
+    def testSi2Q(self):
+        self.vty.enable()
+        self.vty.command("configure terminal")
+        self.vty.command("network")
+        self.vty.command("bts 0")
+        before = self.vty.command("show running-config")
+        self.vty.command("si2quater neighbor-list add earfcn 1911 threshold 11 2")
+        self.vty.command("si2quater neighbor-list add earfcn 1924 threshold 11 3")
+        self.vty.command("si2quater neighbor-list add earfcn 2111 threshold 11")
+        self.vty.command("si2quater neighbor-list del earfcn 1911")
+        self.vty.command("si2quater neighbor-list del earfcn 1924")
+        self.vty.command("si2quater neighbor-list del earfcn 2111")
+        self.assertEquals(before, self.vty.command("show running-config"))
+
     def testEnableDisablePeriodicLU(self):
         self.vty.enable()
         self.vty.command("configure terminal")