base.install: Don't allow build on 32bit OS

Current x86 servers are all running in 64bit.
It's pretty useless getting a support for 32bit build env.
grapher: Removing scatterplot

This rendering isn't that useful for now.
Let's remove it not to confuse users.
base.install: Don't allow build on 32bit OS

Current x86 servers are all running in 64bit.
It's pretty useless getting a support for 32bit build env.
Merge branch 'benchgraphs'
git: Adding gitignore

Useful to avoid png listed as untracked
quality: Cleaning code (1/2)

First pass to clean code to let 'make quality happy'
detect.py: fix quality
quality: Cleaning code (2/2)

2nd pass to clean code to let 'make quality' happy
{pxe|health}: Reporting git hash during boot

If edeploy pxe or health initrd got built on top of a git repo, let's
report the version during the boot.

This could avoid searching to solve already solved bugs... sometimes
only the ramfs didn't got rebuilt or not properly booted.

A typical output looks like:

 Info: Probing ipmi_devintf failed
 Info: Added fake IPMI device
 Required kernel modules for 3.2.0-4-amd64 x86_64 are : ata_piix,
 piix4_smbus, virtio-pci,
 Running eDeploy with git hash = 718aa6438dade62354c809b630a3171266054c41
 ################################################################
 Configuring system via server 10.0.2.2
 ################################################################
health: Don't run too big memory tests

While running the memory test, it's important checking that we are not
testing more than the available memory unless we'll face some OOMs.

All tests requiring too much memory will be ignored.
health: Let's print git rev before running tests

As per commit 4b861c39bab5b8029b6a59f6d257e8446960afe8, let's print the
git revision before running the tests.

It could be useful to determine what code is running.
health-check: Fixing MB/s detection

Prior this patch, we were changing B/s before MB/s leading to a trailing
'M'.

It's important removing MB and KB before removing B.
health-check: Let's do destructive tests first

destructive tests shall be done _before_ doing the read test to avoid
fake reads like VMware does. VMware considers that reading from a device
that never been wrote should get IOs from the memory and not from the
device.

Commiting writes first avoid this effect. Note that randread can remain
partially wrong and randomwrite are not obviously getting the same
pattern.
health-check: Quality commit

Let's make health-check much more flake compliant