app_dahdimonitor: Remove superfluous warning.

DAHDIMonitor() could emit a warning once every 20ms, due to read
failing with EAGAIN, but this is normal behavior and was expected.
As such, remove the warning altogether since there is not actually
anything wrong when this happens, and the audio stream is working
as expected.

Author: InterLinked1

apps/app_dahdimonitor.c

@@ -272,15 +272,14 @@ static int dahdi_monitor_exec(struct ast_channel *chan, const char *data)
 					/* Sometimes DAHDI resources like to be temporarily unavailable.
 					 * DAHDI_POLICY_IMMEDIATE also makes this more likely
 					 * (see https://support.digium.com/s/article/How-to-configure-DAHDI-buffer-policies)
+					 * This is normal and expected.
 					 * Don't abort if this happens, just keep trying
 					 * in case the channel becomes available again soon.
 					 * To avoid having a super tight loop (dozens per millisecond),
 					 * skip reading from DAHDI the next iteration,
-					 * and just use the Asterisk channel for timing, which will limit
-					 * how often this error message appears and temper CPU usage.
+					 * and just use the Asterisk channel for timing, which will temper CPU usage.
 					 */
 					skip_dahdi = 1;
-					ast_log(LOG_WARNING, "Failed to read from DAHDI channel %d: %s\n", dahdichan, strerror(errno));
 					continue;
 				}
 				ast_log(LOG_ERROR, "Failed to read from DAHDI channel %d: %s\n", dahdichan, strerror(errno));