[Nightly Tests] Installation Guide Test needs to be fixed

[mbaijal]

The script to test the installation guide run_test_installation_docs.sh has some issues that need to be fixed particularly the first one -

1. It is parsing the index.md incorrectly for the CPU test for build from source. It is running the GPU make steps with the USE_CUDA flag on. Hence this test fails when I run the CPU test on a CPU only instance.
2. the script expects a sudo in the docs/install/index.md pip install mxnet steps. The test script should be modified so that it runs the install steps with the right permissions or prepends the sudo before running the install steps. The install guide (index.md) should not be modified
3. This test script requires 3 parameters - name of the install file, and the start and end line numbers. The first paramater should be enough and the remaining two should be calculated by the test script if required.

[vrakesh]

Thank you for reporting the issue in the script @mbaijal , @sandeep-krishnamurthy requesting this be tagged under bug

[piyushghai]

Not sure if bug is the correct label for this issue.
@mxnet-label-bot Update [Test, Website, Disabled test]