This is in the case if first answer does not work The latest version of git does not require to set proxy it directly uses system proxy settings .so just do these
unset HTTP_PROXY
unset HTTPS_PROXY
in some systems you may also have to do
unset http_proxy
unset https_proxy
if you want to permanantly remove proxy then
sudo gsettings set org.gnome.system.proxy mode 'none'