entity-manager: srcrev bump 1a7c37087d..12bc7931b4

Ed Tanous (4):
      Simplify mux symlink logic
      Fix rstrip on Fru read
      Add M.2 Mux to WFT Baseboard
      Fix an issue with $index

James Feist (2):
      Out of tree build: Add nlohmann as valijson depend
      Rename Front Panel Stepwise curve

(From meta-phosphor rev: 3383e74bbfe6632230e38a8676d9ae385f32add1)

Change-Id: I1f5435bd9a130e2dbc26009f2f341d51756debca
Signed-off-by: Andrew Geissler <openbmcbump-github@yahoo.com>
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>