Fix regression in Exchange 2007 over Dav session

git-svn-id: http://svn.code.sf.net/p/davmail/code/trunk@1451 3d1905a2-6b24-0410-a738-b14d5a86fcbd

src/java/davmail/exchange/dav/DavExchangeSession.java

@@ -498,7 +498,7 @@ public class DavExchangeSession extends ExchangeSession {
 
             getEmailAndAliasFromOptions();
             // failover: try to get email through Webdav and Galfind
-            if (mailPath == null || email == null) {
+            if (alias == null || email == null) {
                 try {
                     buildEmail(method.getURI().getHost());
                 } catch (URIException uriException) {