Issue title: building kernel filled all free disk space
 Issue body: i ran your scripts and they took about 3GB of disk space.
That was all i need, now my jetson has no free disk space anymore.

Where did this space go? the folder where i executed it is very small. where are the 3GB?

Please help
 Comments: 
 Comment 0: After flashing the TX2, there is approximately 8GB used if the Jetson was flashed with the standard libraries, specialty libraries and samples.

The compressed kernel source files are: 138.6 MB
/usr/src/public_release which are the decompressed source files: 122MB
/usr/src/hardware source files: 2MB
/usr/src/kernel source files and compiled object files: 3.9 GB
If you set your local version to something other than 4.4.38-tegra, the compiled modules take up about 113.3 MB.

I am not sure why you are asking me to provide this information. On a TX2 this does not kill all free disk space, typically there are over > 15GB free after building a kernel and modules.

All of this is covered in the article: http://www.jetsonhacks.com/2018/03/22/build-kernel-modules-nvidia-jetson-tx2-2/
In the YouTube video: https://www.youtube.com/watch?v=80c5j0rSN_0
You could also read the code as a last resort.

 Comment 1: i was using this for installing librealsense.
Their installation guide used this repo as workaround for jetsons.

My jetson was all setup and running, but running through the scripts in this repo filled my remaining 3gb, probably it would have taken more, but it obviously stopped after the disk was full.

Now i am unable to reboot the jetson :/
 Comment 2: Those are the correct sizes.
You can erase all of the kernel/module files source and build files:

$ sudo rm -r /usr/src/kernel
$ sudo rm -r /usr/src/hardware
$ sudo rm -r /usr/src/public_release
$ sudo rm -r /usr/src/source_release.tbz2

You can also delete the build kernel repository:

$ cd ~/
$ sudo rm -r buildJetsonTX2Kernel

This should remove everything installed by the buildJetsonTX2Kernel.



 Comment 3: a perfectly thanks! Why are those files created? as backup?
 Comment 4: They are created to compile the kernel and module source files.
 Comment 5: is it also safe to delete` /usr/src/linux-headers-4.4.38-tegra` ?
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