glsl: Remove extraneous .dir-locals.el

This was overriding the top-level .dir-locals.el causing some settings
(like forcing spaces instead of tabs!) to be lost.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/glsl/.dir-locals.el

@@ -1,3 +0,0 @@
-((c-mode . ((c-basic-offset . 3)))
- (c++-mode . ((c-basic-offset . 3)))
-)