overlay: Fix missing space in error message

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Change-Id: Ia950f27295166b65155df65aa998f4328c509279
diff --git a/src/overlay.cpp b/src/overlay.cpp
index 1d99a79..defa5ad 100644
--- a/src/overlay.cpp
+++ b/src/overlay.cpp
@@ -96,7 +96,7 @@
             devDir / ("channel-" + std::to_string(channelIndex));
         if (!is_symlink(channelPath))
         {
-            std::cerr << channelPath << "for mux channel " << *channelName
+            std::cerr << channelPath << " for mux channel " << *channelName
                       << " doesn't exist!\n";
             continue;
         }