[httpclient] Logging change

[Vincent Massol]

Could someone make the following changes to httpclient :

* when no httpclient.log property is defined, use Log4j by default if found
in classpath or NoOpLog as a second solution. For the moment if
httpclient.log is not found, it uses NoOpLog.

* Use the following conversion pattern in conf/log4j.properties.sample : "
%d{ABSOLUTE} [%t] %-5p %-30.30c{2} %x - %m %n ". I find it much more
readable. That's my favorite one, tell me if you like it  :)

Thanks
-Vincent