Remove quotes from Windows echo

Quotes are unnecessary on windows, and end up in the final output of the
echo.

Change-Id: I399959710a4c926648e9333bd808d8f094c6e0e6

pw_env_setup/py/pw_env_setup/environment.py

diff --git a/pw_env_setup/py/pw_env_setup/environment.py b/pw_env_setup/py/pw_env_setup/environment.py
index 3087168..56de17a 100644
--- a/pw_env_setup/py/pw_env_setup/environment.py
+++ b/pw_env_setup/py/pw_env_setup/environment.py
@@ -155,7 +155,7 @@
         # POSIX shells parse arguments and pass to echo, but Windows seems to
         # pass the command line as is without parsing, so quoting is wrong.
         if windows:
-            outs.write('echo "{}"\n'.format(self.value))
+            outs.write('echo {}\n'.format(self.value))
         else:
             # TODO(mohrr) use shlex.quote().
             outs.write('if [ -z "${PW_ENVSETUP_QUIET:-}" ]; then\n')