CMIS-907: fixed SPI class check

git-svn-id: https://svn.apache.org/repos/asf/chemistry/dotcmis/trunk@1672292 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/DotCMIS/binding/binding-intf.cs b/DotCMIS/binding/binding-intf.cs
index 0e0a910..ff6822b 100644
--- a/DotCMIS/binding/binding-intf.cs
+++ b/DotCMIS/binding/binding-intf.cs
@@ -371,7 +371,7 @@
             {

                 string spiClass;

 

-                if (sessionParameters.TryGetValue(SessionParameter.BindingSpiClass, out spiClass))

+                if (!sessionParameters.TryGetValue(SessionParameter.BindingSpiClass, out spiClass))

                 {

                     throw new ArgumentException("SPI class entry (" + SessionParameter.BindingSpiClass + ") is missing!");

                 }