rtl: pass exact size to delete instead of full string length

git-svn-id: trunk@22418 -

rtl/unix/sysunix.inc

@@ -36,7 +36,7 @@ begin
     p:=Pos('.',Result);
     if p>0 then Delete(Result,1,p);
     p:=Pos('@',Result);
-    if p>0 then Delete(Result,p,length(Result));
+    if p>0 then Delete(Result,p,length(Result)-p+1);
   end;
 end;