Extend pillar include support so that nesting is possible
for the key directive.
Given the following pillar files:
foo1.sls:
include:
- foo:
key: two:levels
foo2.sls:
foon: blah
After this commit, it'll result in the following pillar data:
two:
levels:
foon: blah
Currently, it results in the following data which is far less useful
for usage, and in ability to be addressed:
two:levels:
foon: blah
