Corrected 'illegal pattern' syntax error.

Replaced a "!" with a "," to correct "illegal pattern" 
````
$ erlc demo1.erl
demo1.erl:13: 
demo1.erl:13: illegal pattern
demo1.erl:14: variable 'From' is unbound
demo1.erl:14: variable 'N' is unbound
````

Complete corrected sample: https://gist.github.com/bryanhunter/7994399