Revert "osd: create the erasure-code ruleset in OSDMap::build_simple"

This reverts commit b85330eb1d62632a1c3f2025b1f309816d54bd5a.

We can't have this in the OSDMap by default or else all clients will require
the new features.

[Fixed up #include for strmap]

Signed-off-by: Sage Weil <sage@inktank.com>
osd: fix tests due to no default erasure-code ruleset

Signed-off-by: Sage Weil <sage@inktank.com>