add gtest as a testtime dep
add gtest as a testtime dep

(it's still a builddep for retro-compat)

Change-Id: I119158135666e950f2a872ab4f2627232a8db42e
Reviewed-on: http://gerrit.aldebaran.lan/25680
Reviewed-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>
Tested-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>

aldebaran/libqi,aldebaran/libqi,bsautron/libqi,vbarbaresi/libqi,aldebaran/libqi