Fix IMAP hang on auth failure

This closes Bug 1007
Thanks to Francois Andriot for the patch!
(cherry picked from commit aa2af2573b)

kioslaves/imap4/imapparser.cc

@@ -277,11 +277,11 @@ imapParser::clientAuthenticate ( KIO::SlaveBase *slave, KIO::AuthInfo &ai,
   }
   cmd = sendCommand (new imapCommand ("AUTHENTICATE", firstCommand.latin1()));
 
-  while ( true )
+  int pl = 0;
+  while ( pl != -1 && !cmd->isComplete () )
   {
     //read the next line
-    while (parseLoop() == 0) ;
-    if ( cmd->isComplete() ) break;
+    while ((pl = parseLoop()) == 0) ;
 
     if (!continuation.isEmpty())
     {