glmark2: bump version to fix build

The package otherwise fails to build with a recent toolchain with GCC6
(tested with Linaro ARM 2016.11).

It used to fail at sqrt check during package configuration:
 Checking for function sqrt               : not found
 The configuration failed

Bumping version to latest HEAD fixes the issue as explained in the
following discussion:
https://github.com/glmark2/glmark2/issues/15

Fixes:

  http://autobuild.buildroot.net/results/8dc9400505b9087ce290981d95486598df0beb56/



Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
[Thomas: add reference to autobuilder failure.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>