[gnome-builder] rust: setup PATH for rustc access when necessary

[Christian Hergert <chergert src gnome org>]

commit bef2f9de336d106571625d4786dbc23723c36b6e
Author: Christian Hergert <chergert redhat com>
Date:   Wed Mar 29 19:56:56 2017 -0600

    rust: setup PATH for rustc access when necessary

 plugins/rust-langserv/rust_langserv_plugin.py |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/plugins/rust-langserv/rust_langserv_plugin.py b/plugins/rust-langserv/rust_langserv_plugin.py
index 49cbb05..4955534 100644
--- a/plugins/rust-langserv/rust_langserv_plugin.py
+++ b/plugins/rust-langserv/rust_langserv_plugin.py
@@ -89,7 +89,9 @@ class RustService(Ide.Object, Ide.Service):
             # If rls was installed with Cargo, try to discover that
             # to save the user having to update PATH.
             path_to_rls = os.path.expanduser("~/.cargo/bin/rls")
-            if not os.path.exists(path_to_rls):
+            if os.path.exists(path_to_rls):
+                launcher.setenv('PATH', os.path.expanduser("~/.cargo/bin"), True)
+            else:
                 path_to_rls = "rls"
 
             # Setup our Argv. We want to communicate over STDIN/STDOUT,