Revert "Update INSTALL_UBUNTU.md"

This reverts commit 9ba3644d.

INSTALL_UBUNTU.md

-Install blaar on Ubuntu
-=======================
+Install blaar on Ubuntu or Raspbian (rasperry pi)
+=================================================
 
 Copy past this line in a terminal
 
-    wget -q  -O/tmp/blaar_install.sh  https://git.blaar.org/blaar/blaar/raw/master/developer_tools/clone_and_install_blaar_ubuntu.sh && bash /tmp/blaar_install.sh; rm /tmp/blaar_install.sh; cd blaar
+    wget -q  -O/tmp/blaar_install.sh  https://promethe.u-cergy.fr/blaar/blaar/raw/master/developer_tools/clone_and_install_blaar_ubuntu.sh &&
+    bash /tmp/blaar_install.sh; rm /tmp/blaar_install.sh; cd blaar
     
 
 You will be requested at some point to enter your admin password to make the installation.
 
-You can do [**step by step**](https://git.blaar.org/blaar/blaar/blob/master/developer_tools/clone_and_install_blaar_ubuntu.sh) copying command line by command line. This may be useful to better understand and in case where the installer crash.
+You can do [**step by step**](https://promethe.u-cergy.fr/blaar/blaar/blob/master/developer_tools/clone_and_install_blaar_ubuntu.sh) copying command line by command line. This may be useful to better understand and in case where the installer crash.