[Beignet] apply 75cb7ca to 1.2 branch?

[Rebecca N. Palmer]

When beignet 1.2.1 is built with LLVM 3.9,
OCL_STRICT_CONFORMANCE=0 utest_run -c vload_test_uchar
(and other vload_test_*) hang during kernel compile, deep inside LLVM.

This does not happen in master; a bisect finds the fix to be 75cb7ca,
and applying this to 1.2.1 (at least in the Debian package) does fix
the problem, but I don't know why.

Hardware:
00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)