Rename mode clap parameter to permissions

Rename the clap parameter when creating a new message queue `mode` to
`permissions`.

src/create.rs

@@ -7,8 +7,8 @@ use std::fs;
 #[derive(Clap, Debug)]
 pub struct Create {
     /// Permissions (octal) to create the queue with
-    #[clap(short = 'p', long)]
-    mode: Option<String>,
+    #[clap(short, long)]
+    permissions: Option<String>,
     /// Maximum number of messages in the queue
     #[clap(short, long)]
     capacity: Option<usize>,
@@ -38,7 +38,7 @@ impl Create {
     pub fn run(&self, verbose: bool) -> Result<()> {
         let mq = &mut posixmq::OpenOptions::readonly();
 
-        if let Some(m) = &self.mode {
+        if let Some(m) = &self.permissions {
             mq.mode(u32::from_str_radix(&m, 8)?);
         }