Fix number of available GPUs in the installer script

[ssheikholeslami]

The command sudo lspci | grep -i nvidia that is used to initialize the number of available GPUs might return inaccurate information, e.g., in my machine with 4 nvidia GPUs it outputs:

09:00.1 Audio device: NVIDIA Corporation Device 10f8 (rev a1)
09:00.2 USB controller: NVIDIA Corporation Device 1ad8 (rev a1)
09:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1)
0a:00.0 VGA compatible controller: NVIDIA Corporation Device 1e84 (rev a1)
0a:00.1 Audio device: NVIDIA Corporation Device 10f8 (rev a1)
0a:00.2 USB controller: NVIDIA Corporation Device 1ad8 (rev a1)
0a:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1)
42:00.0 VGA compatible controller: NVIDIA Corporation Device 1e84 (rev a1)
42:00.1 Audio device: NVIDIA Corporation Device 10f8 (rev a1)
42:00.2 USB controller: NVIDIA Corporation Device 1ad8 (rev a1)
42:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1)
43:00.0 VGA compatible controller: NVIDIA Corporation Device 1e84 (rev a1)
43:00.1 Audio device: NVIDIA Corporation Device 10f8 (rev a1)
43:00.2 USB controller: NVIDIA Corporation Device 1ad8 (rev a1)
43:00.3 Serial bus controller [0c80]: NVIDIA Corporation Device 1ad9 (rev a1)

Hence, the installer will assume that the machine has 16 GPUs.
A workaround is to modify the existing command to only consider the lines with "VGA".

A better fix is to use nvidia-smi -L | wc -l instead, but the nvidia driver and nvidia-smi might not be installed on the machine when we initialize those variables.

[jimdowling]

Thanks Sina!
However, we assume nvidia-smi isn't installed at that stage.
I could add a check for 'VGA', which i think is normally found.