Ensure the correct value is returned for CHANNEL(pjsip, secure)

Prior to this patch, we were using the PJSIP dialog's secure flag
to determine if a secure transport was being used. Unfortunately,
the dialog's secure flag was only set if a SIPS URI were in use,
as required by RFC 3261 sections 12.1.1 and 12.1.2. What we're interested
in is not dialog security, but transport security. This code change
switches to a model where we use the dialog's target URI to determine
what transport would be used to communicate, and then check if that
transport is secure.

AST-1450 #close
Reported by John Bigelow

Review: https://reviewboard.asterisk.org/r/4277



git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/13@429739 f38db490-d61c-443f-a65b-d21fe96a405b
Prevent possible race condition on dual redirect of channels in the same bridge.

The AST_FLAG_BRIDGE_DUAL_REDIRECT_WAIT flag was created to prevent bridges from
prematurely acting on orphaned channels in bridges. The problem with the AMI
redirect action was that it was setting this flag on channels based on the presence
of a PBX, not whether the channel was in a bridge. Whether a channel has a PBX
is irrelevant, so the condition has been altered to check if the channel is in a
bridge.

ASTERISK-24536 #close
Reported by Niklas Larsson

Review: https://reviewboard.asterisk.org/r/4268



git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/13@429741 f38db490-d61c-443f-a65b-d21fe96a405b