clippy: Resolve needless_return

TEST=bin/clippy

Change-Id: I62eb3f86b01a6000107c54a967689d4e430adf50
Reviewed-on: https://chromium-review.googlesource.com/1566743
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

bin/clippy

@@ -14,7 +14,6 @@ cd ..
 SUPPRESS=(
     # To be resolved.
     let_unit_value
-    needless_return
     option_map_unit_fn
     question_mark
     range_plus_one

src/plugin/mod.rs

@@ -733,11 +733,11 @@ pub fn run_config(cfg: Config) -> Result<()> {
 
     match plugin.try_wait() {
         // The plugin has run out of time by now
-        Ok(ProcessStatus::Running) => return Err(Error::PluginTimeout),
+        Ok(ProcessStatus::Running) => Err(Error::PluginTimeout),
         // Return an error discovered earlier in this function.
-        Ok(ProcessStatus::Success) => return res,
-        Ok(ProcessStatus::Fail(code)) => return Err(Error::PluginFailed(code)),
-        Ok(ProcessStatus::Signal(code)) => return Err(Error::PluginKilled(code)),
-        Err(e) => return Err(Error::PluginWait(e)),
-    };
+        Ok(ProcessStatus::Success) => res,
+        Ok(ProcessStatus::Fail(code)) => Err(Error::PluginFailed(code)),
+        Ok(ProcessStatus::Signal(code)) => Err(Error::PluginKilled(code)),
+        Err(e) => Err(Error::PluginWait(e)),
+    }
 }

vm_control/src/lib.rs

@@ -321,7 +321,7 @@ impl VmRequest {
                     Ok(response) => VmResponse::UsbResponse(response),
                     Err(e) => {
                         error!("fail to recv command from usb control socket: {}", e);
-                        return VmResponse::Err(SysError::new(EIO));
+                        VmResponse::Err(SysError::new(EIO))
                     }
                 }
             }