Increase the size of the QHostInfo cache.

This change increases the size of the DNS cache in QHostInfo from 64
entries to 128. Given the figures in the google chrome performance paper
http://www.igvita.com/posa/high-performance-networking-in-google-chrome/
this should mean we can cache enough entries to handle 4 tabs at once.

Change-Id: I34e32e9e0966473591c59ca5f222623a354650d2
Reviewed-by: Peter Hartmann <phartmann@rim.com>

src/network/kernel/qhostinfo.cpp

@@ -699,8 +699,8 @@ void Q_AUTOTEST_EXPORT qt_qhostinfo_enable_cache(bool e)
 }
 
 // cache for 60 seconds
-// cache 64 items
-QHostInfoCache::QHostInfoCache() : max_age(60), enabled(true), cache(64)
+// cache 128 items
+QHostInfoCache::QHostInfoCache() : max_age(60), enabled(true), cache(128)
 {
 #ifdef QT_QHOSTINFO_CACHE_DISABLED_BY_DEFAULT
     enabled = false;