Fix segfault in IMAP folder parsing

Thanks to Francois Andriot for the patch!
(cherry picked from commit 9b43d6e180)

kioslaves/imap4/imapparser.cc

@@ -1354,10 +1354,10 @@ void imapParser::parseBody (parseString & inWords)
         label = parseOneWordC (inWords);
       }
 
-      if (inWords[0] == ')')
+      if (!inWords.isEmpty () && inWords[0] == ')')
         inWords.pos++;
     }
-    if (inWords[0] == ']')
+    if (!inWords.isEmpty () && inWords[0] == ']')
       inWords.pos++;
     skipWS (inWords);
 
@@ -1479,6 +1479,7 @@ void imapParser::parseFetch (ulong /* value */, parseString & inWords)
     {
       TQCString word = parseLiteralC(inWords, false, true);
 
+      if(!word.isEmpty()) {
       switch (word[0])
       {
       case 'E':
@@ -1602,6 +1603,9 @@ void imapParser::parseFetch (ulong /* value */, parseString & inWords)
         parseLiteralC(inWords);
         break;
       }
+      } else {
+        parseLiteralC(inWords);
+	  }
     }
   }