Move all the BuildRequires higher in the spec and add the missing one on git
    
    BuildRequires are for the entire spec file they do not depend on sub-packages
    so it does not make sense to tie them with one.
    
    We also need to have ``git`` installed in the buildroot for the test to run
    successully, so we're adding it to the list of BuildRequires while at it.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>