qi.messaging: Remove increasing of `ServiceDirectoryProxy` attachment retry delay.
qi.messaging: Remove increasing of `ServiceDirectoryProxy` attachment retry delay.

This behavior was implemented to preemptively avoid overloading the
system when several proxies would retry connecting to service
directories at the same time.

But it is detrimental to the starting time of the system, which is
critical.

Change-Id: Ib2e502b1bd815a20ff33a286726f356c333271cb
Reviewed-on: http://gerrit2.aldebaran.lan/387
Reviewed-by: philippe.martin <a3db8b74c3cf86a5cf091dca4e2125b498be933d@softbankrobotics.com>
Reviewed-by: vincent.palancher <f8ff75e1c61314c499fafa8de0d9e004e87e66b0@softbankrobotics.com>
Reviewed-by: jmonnon <8898eaf233516e520f996a244ca8a12d20f948b1@aldebaran.com>
Reviewed-by: jlamotte <70353e7b0c7d18b7fc75605daf0ccba69fcd3222@aldebaran.com>
Tested-by: vincent.palancher <f8ff75e1c61314c499fafa8de0d9e004e87e66b0@softbankrobotics.com>

aldebaran/libqi,aldebaran/libqi,aldebaran/libqi