RootShell: multiplex commands

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/android/util/ToolsInstaller.java

@@ -65,6 +65,10 @@ public final class ToolsInstaller {
                     new File(installDir, names[1]),
                     new File(installDir, names[1])));
         }
-        return rootShell.run(null, script.toString());
+        try {
+            return rootShell.run(null, script.toString());
+        } catch (Exception e) {
+            return OsConstants.EACCES;
+        }
     }
 }