README.md: Remove --enable-debug option for masterfiles

There is no `--enable-debug` options for the configure script in
masterfiles.

```
./autogen.sh --enable-debug
 ---snip---
configure: WARNING: unrecognized options: --enable-debug
```

Signed-off-by: Lars Erik Wik <lars.erik.wik@northern.tech>

Author: larsewi

README.md

@@ -177,7 +177,7 @@ Configure the Masterfiles Policy Framework:
 
 ```
 cd ../masterfiles
-./autogen.sh --enable-debug
+./autogen.sh
 ```
 
 ### Installing CFEngine Community on a test machine