Update NEWS for unreleased 2.4.5

I need this for another 2.5 release.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>

NEWS

 News
 ====
 
+Version 2.4.5
+-------------
+
+*(unreleased)*
+
+- Fixed bug when parsing command line parameter values ending in
+  backslash
+- Fixed assertion error after unclean master shutdown
+- Disable HTTP client pool for RPC, significantly reducing memory usage
+  of master daemon
+
+
 Version 2.4.4
 -------------