iCubGui: In BVHNodeEYE switch from glutSolidSphere to gluSphere

[traversaro]

I am not an expert of glut, but apparently there are functions that start with glu*** and take in input a pointer to GLUquadricObj, and functions that start with glut and do not take in input a pointer to GLUquadricObj. BVHNodeEYE was the only class that used a glut*** function, and during the call when used with freeglut installed via vcpkg it was crashing with error:

Exception thrown: read access violation.
fgStructure.**CurrentWindow** was nullptr. occurred

and the backtrace was:

 	freeglutd.dll!fghDrawGeometrySolid(float * vertices, float * normals, float * textcs, int numVertices, wchar_t * vertIdxs, int numParts, int numVertIdxsPerPart) Line 181	C
 	freeglutd.dll!fghSphere(float radius, int slices, int stacks, unsigned char useWireMode) Line 1721	C
 	freeglutd.dll!glutSolidSphere(double radius, int slices, int stacks) Line 2066	C
>	iCubGui.exe!BVHNodeEYE::drawJoint() Line 34	C++

Changing from glutSolidSphere to gluSphere as done the other classes that inherit from BVHNodeDH fixes the crash.

Fix robotology/robotology-superbuild#355 .

[Nicogene]

I am not an expert of glut either, but your analysis make sense to me.
LGTM 👍

[traversaro]

@pattacini let me know if you want to handle the merge + merge forward or do you prefer if I do it.

[pattacini]

I'll deal with devel, no problem!
Thanks for the fix 👍