msmtpq: Create queue directory automatically

If the queue directory is not present, there is no reason to complain as
we can just create it automatically.

This is a quality of life improvement so that people don't have to
remember to create ~/.msmtp.queue on new setups before this script
starts working.

Due to the previous "-d $Q" test, it is only called if the directory
does not exist yet, therefore the "-p" flag is not needed to prevent
mkdir from failing if the directory exists already.

With this patch, this script can finally run with zero prior
configuration.

scripts/msmtpq/msmtpq

@@ -71,8 +71,8 @@ MSMTP=msmtp
 ##
 ## the queue dir - modify this to reflect where you'd like it to be  (no quotes !!)
 Q=~/.msmtp.queue
-[ -d "$Q" ] || \
-  err '' "msmtpq : can't find msmtp queue directory [ $Q ]" ''     # if not present - complain ; quit
+[ -d "$Q" ] || mkdir -m 0700 "$Q" || \
+  err '' "msmtpq : can't find or create msmtp queue directory [ $Q ]" ''     # if not present - complain ; quit
 ##
 ## set the queue log file var to the location of the msmtp queue log file
 ##   where it is or where you'd like it to be