aixPb: Put /usr/bin in front of PATH

[Haroon-Khel]

• commit message has one of the standard prefixes
• faq.md updated if appropriate
• other documentation is changed or added (if applicable)
• playbook changes run through VPC or QPC (if you have access)
• VPC/QPC not applicable for this PR
• for inventory.yml changes, bastillion/nagios/jenkins updated accordingly

To escape the rebase hell that is #2288, ive simply created a new pr :)

[sxa]

Why is /etc in there? I can't think of anything we need in the PATH that would be in there

[Haroon-Khel]

Not sure. I'll remove it

[steelhead31]

Looks ok.

[sxa]

We should also bear in mind that while this will be ok for new machines it likely won't change the existing machines which have PATH=/opt/freeware/bin at the start as most machines currently won't match this regex, so if we don't put another case in here for that we'll need to look at patching the existing machines up (as described in #2288 (comment)). Also noting that this regex to update the config will trigger on every playbook execution since it sets the path to something that has PATH=/usr/bin at the start. Something like @aixtools' proposal in #2288 (review) may be preferable, but I'm also ok with a one-off manual fixup.

[karianna]

We should also bear in mind that while this will be ok for new machines it likely won't change the existing machines which have PATH=/opt/freeware/bin at the start as most machines currently won't match this regex, so if we don't put another case in here for that we'll need to look at patching the existing machines up (as described in #2288 (comment)). Also noting that this regex to update the config will trigger on every playbook execution since it sets the path to something that has PATH=/usr/bin at the start. Something like @aixtools' proposal in #2288 (review) may be preferable, but I'm also ok with a one-off manual fixup.

holding off merging until we raise any appropriate work items here for consistency.

[Haroon-Khel]

I've manually updated the PATH on the current machines to start with /usr/bin:/opt/IBM/xlC/13.1.3/bin:/opt/freeware/bin: