geckodriver: marionette: append X11 style -marionette flag when start…

…ing browser

jgraham/rust_mozrunner#7 was recently submitted
to make mozrunner not imply starting the Marionette server by passing the
--marionette flag.  This patch appends -marionette, with a single dash,
so that it will be accepted on Windows systems.

More discussion around this in
mozilla/geckodriver@2e0054b.

Fixes: mozilla/geckodriver#640
Source-Repo: https://github.com/mozilla/geckodriver
Source-Revision: 7c577c04176c1cc7b5bd45928b3a36bd1818c5ae

committer: jgraham <jameshoppipolla.co.uk>

UltraBlame original commit: 0663affcced9ec002c219ec077d62817c6a4ae9a

testing/geckodriver/src/marionette.rs

@@ -2262,6 +2262,32 @@ to_owned
 )
 )
 ;
+/
+/
+double
+-
+dashed
+flags
+are
+not
+accepted
+on
+Windows
+systems
+runner
+.
+args
+(
+)
+.
+push
+(
+"
+-
+marionette
+"
+)
+;
 if
 let
 Some