Emacs auto-detects the build-aux/test-driver.scm as sh-mode, due to the
shebang. So override the auto-detection using a local variable forcing
scheme-mode.
* build-aux/test-driver.scm: Set mode to scheme.
Change-Id: I07f12656dba5fb7b52447b94569307a2a605ffc1
Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>