Set project path as cwd for rls processes

This fixes some issues with latest nightly rls/cargo

Author: alexheretic

lib/index.js

@@ -394,7 +394,7 @@ class RustLanguageClient extends AutoLanguageClient {
       !filePath.includes('/target/release/')
   }
 
-  startServerProcess() {
+  startServerProcess(projectPath) {
     let cmdOverride = rlsCommandOverride()
     if (cmdOverride) {
       if (!this._warnedAboutRlsCommandOverride) {
@@ -404,15 +404,17 @@ class RustLanguageClient extends AutoLanguageClient {
       }
       return cp.spawn(cmdOverride, {
         env: serverEnv(),
-        shell: true
+        shell: true,
+        cwd: projectPath
       })
     }
 
     return checkToolchain(this.busySignalService)
       .then(toolchain => checkRls(this.busySignalService).then(() => toolchain))
       .then(toolchain => {
         return cp.spawn("rustup", ["run", configToolchain(), "rls"], {
-          env: serverEnv(toolchain)
+          env: serverEnv(toolchain),
+          cwd: projectPath
         })
       })
   }