Add RFC6643 parser support
RFC6643 defines a way to map SMIv2 to YANG. This mapping retains
the original SMI details using YANG extensions, so that the resulting
model can be mapped back.
This patch adds semantic support for these extensions, so that the
semantics are supported out of the box.
JIRA: YANGTOOLS-1134
Change-Id: I494b2537e89e5a104debe486a9012d22d5c7b3aa
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
(cherry picked from commit
4223bf8c4eae4a003b71554fbcc98b5377ddce2b)
(cherry picked from commit
1200789c3e9591882ef066ecc6bad7f8ff63a7f7)