qt_update_submodules: update credentials used for pushing to gerrit
qt_update_submodules: update credentials used for pushing to gerrit

By default, let the submodule updates come from
qt_submodule_update_bot@ovi.com, as both the author and committer.

Change-Id: I0dbc2443e583af951867aa7e4ff34dcd3be88c7b
Reviewed-on: http://codereview.qt.nokia.com/1334
Reviewed-by: Qt Sanity Bot <5581206bb7e0307f0d99eb71898ae6b694149ca5@ovi.com>
Reviewed-by: Sunil Thaha <228391b6dd71acee382453fba37c2a44674bd107@nokia.com>
Reviewed-by: Rohan McGovern <d75463945f40a9669160a73cef2843e56b22c602@nokia.com>

tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa