include node condition value in check message

[dwradcliffe]

What does this PR do?

Provide additional information in service check message when the node condition check is failing.

Motivation

I was looking at the data we have for a failing kubernetes_state.node.ready service check and it says this:

node:xxx-0000 is currently reporting condition:Ready

The condition is always present, but the value of the condition is the important bit. We should include that in the message.

This PR should change the message to be:

node:xxx-0000 is currently reporting condition:Ready = false

Review checklist

• PR has a meaningful title or PR has the no-changelog label attached
• Feature or bugfix has tests
• Git history is clean
• If PR impacts documentation, docs team has been notified or an issue has been opened on the documentation repo

[codecov-io]

Codecov Report

Merging #2362 into master will increase coverage by 2.7%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2362      +/-   ##
==========================================
+ Coverage      80%   82.71%    +2.7%     
==========================================
  Files         210        4     -206     
  Lines       14447      376   -14071     
  Branches     1561       72    -1489     
==========================================
- Hits        11559      311   -11248     
+ Misses       2488       44    -2444     
+ Partials      400       21     -379

[xvello]

LGTM, thanks for your contribution!