configs, LICENSE: remove pbx.digium.com.

pbx.digium.com no longer accepts IAX2 calls and
there are no plans for it to come back.

Accordingly, nonworking IAX2 URIs are removed from
both the LICENSE file and the sample config.

ASTERISK-29923 #close

Change-Id: I257c54d4d812ed6b4bd4cbec2cd7ebe2b87b5bad

LICENSE

@@ -45,7 +45,7 @@ redistribution of Asterisk source code obtained from Digium, you
 should contact our licensing department to determine the necessary
 steps you must take. For more information on this policy, please read:
 
-http://www.digium.com/en/company/profile/trademarkpolicy.php
+https://www.sangoma.com/wp-content/uploads/Sangoma-Trademark-Policy.pdf
 
 If you have any questions regarding our licensing policy, please
 contact us:
@@ -53,7 +53,6 @@ contact us:
 +1.877.344.4861 (via telephone in the USA)
 +1.256.428.6000 (via telephone outside the USA)
 +1.256.864.0464 (via FAX inside or outside the USA)
-IAX2/pbx.digium.com (via IAX2)
 licensing@digium.com (via email)
 
 Digium, Inc.

configs/samples/extensions.conf.sample

@@ -601,15 +601,6 @@ exten => #,1,Playback(demo-thanks)	; "Thanks for trying the demo"
 exten => t,1,Goto(#,1)			; If they take too long, give up
 exten => i,1,Playback(invalid)		; "That's not valid, try again"
 
-;
-; Create an extension, 500, for dialing the
-; Asterisk demo.
-;
-exten => 500,1,Playback(demo-abouttotry)	; Let them know what's going on
-	same => n,Dial(IAX2/guest@pbx.digium.com/s@default)	; Call the Asterisk demo
-	same => n,Playback(demo-nogo)	; Couldn't connect to the demo site
-	same => n,Goto(s,6)		; Return to the start over message.
-
 ;
 ; Create an extension, 600, for evaluating echo latency.
 ;