qform=2 on t2 data

[jcohenadad]

On the t2/t2.nii.gz data, fslhd gives:

qform_code	2
qto_xyz:1	0.000000 0.000000 1.000000 -32.219284 
qto_xyz:2	-1.000000 0.000000 -0.000000 31.786606 
qto_xyz:3	0.000000 1.000000 -0.000000 -19.321671 
qto_xyz:4	0.000000 0.000000 0.000000 1.000000 
qform_xorient	Anterior-to-Posterior
qform_yorient	Inferior-to-Superior
qform_zorient	Left-to-Right
sform_name	Aligned Anat
sform_code	1
sto_xyz:1	0.000000 0.000000 1.000000 -32.219284 
sto_xyz:2	-1.000000 0.000000 0.000000 31.786606 
sto_xyz:3	0.000000 1.000000 0.000000 -19.321671 
sto_xyz:4	0.000000 0.000000 0.000000 1.000000 

qform_code=2 means that the physical coordinate system is "unknown" and that some software will then consider the sform instead.

I think we should set the qform_code=1 for our testing data, because this is how we expect NIFTI header to be presented to SCT's functions.

Related to spinalcordtoolbox/spinalcordtoolbox#3283