Resolve conflicts between CONFFLAG_DONT_DENOISE and CONFFLAG_INTROUSER_VMREC

Resolve conflicts between CONFFLAG_DONT_DENOISE and CONFFLAG_INTROUSER_VMREC

When r382230 added an option to not denoise the MeetMe conference (if a user
had a channel whose format's sample rate changed frequently, for example),
the value added was the maximum allowed value for the constants that define
the options for MeetMe in 1.8. Not so in 11 - unfortunately, the option
CONFFLAG_DONT_DENOISE conflicts with CONFFLAG_INTROUESR_VMREC. This patch
fixes that, and also tweaks one of the way in which the constants was
declared for consistency.

Thanks to Tony Mountifield for pointing out the problem and solution.

(closes issue ASTERISK-22269)
Reported by: Tony Mountifield

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@396944 65c4cc65-6c06-0410-ace0-fbb531ad65f3