README: Improve my-email-lda script

In case someone may want to simply copy/paste the example, make that
possible by providing the necessary shebang and properly quote the log
file argument.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

doc/README

diff --git a/doc/README b/doc/README
index 18be35b..c2ebd1f 100644
--- a/doc/README
+++ b/doc/README
@@ -84,7 +84,8 @@
 the options we needed:
 
 $ cat /home/aiaiai/bin/my-aiaiai-lda
-$HOME/git/email/aiaiai-email-lda -v --reap-archive=43200 --reap-incomplete=10 -- $HOME/aiaiai-workdir >> $HOME/aiaiai-logs/email-lda.log" 2>&1
+#!/bin/sh
+$HOME/git/email/aiaiai-email-lda -v --reap-archive=43200 --reap-incomplete=10 -- $HOME/aiaiai-workdir >> "$HOME/aiaiai-logs/email-lda.log" 2>&1
 
 
 So, aiaiai-email-lda collects patches belonging to the patch-sets, and when it