Attribute set on peer was being overridden when set on the peer-group.
This commit also adds a parallel flags array that indicates whether a
particular flag is sourced from the peer-group or is peer-specific. It
assumes the default state of all flags is unset. This looks to be true
except in the case of PEER_FLAG_SEND_COMMUNITY,
PEER_FLAG_SEND_EXT_COMMUNITY, and PEER_FLAG_SEND_LARGE_COMMUNITY; these
flags are set by default except when the user specifies to use
config-type = cisco. However the flag field can merely be flipped to
mean the negation of those options in a future commit.
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>