Currently using envsubst to perform substitution of value overrides in
the feature gate caused conflicts as gotpl gets templated into those
overrides. This adds in '%%%REPLACE_${var}%%%' and uses sed to perform
the substitution instead to address the issue.
Change-Id: I9d3d630b53a2f3d828866229a5072bb04440ae15
Signed-off-by: Tin Lam <tin@irrational.io>
ac18e6acf9