setup: fix issue while updating remote bare clones
setup: fix issue while updating remote bare clones

The script was doing git clone --bare instead of --mirror, thus preventing
fetching the updated versions when the remote git changed.
This had no impact until now since the remotes were not updated for poky,
meta-mingw and meta-darwin layers.

Tracked-On: EDISON-2489
Signed-off-by: Fabien Chereau <d81c12e10052d5260109f2526904461b0e753738@intel.com>

htot/meta-intel-edison,oesile/meta-intel-edison,htot/meta-intel-edison,oesile/meta-intel-edison,oesile/meta-intel-edison,oesile/meta-intel-edison,htot/meta-intel-edison,htot/meta-intel-edison,oesile/meta-intel-edison,oesile/meta-intel-edison,oesile/meta-intel-edison,htot/meta-intel-edison,oesile/meta-intel-edison