Fixing image typo

With sidecar charms, the image overlay now needs to have
the name of the unit prepended to the image resource.

Change-Id: I4e503137f6d4167904a5654aa7811f84c4374315
Signed-off-by: Mark Beierl <mark.beierl@canonical.com>
diff --git a/installers/charmed_install.sh b/installers/charmed_install.sh
index e7f63b0..dbd307e 100755
--- a/installers/charmed_install.sh
+++ b/installers/charmed_install.sh
@@ -397,7 +397,7 @@
         cat << EOF >> /tmp/images-overlay.yaml
   ${charm}:
     resources:
-      image: /tmp/${charm}_registry.yaml
+      ${charm}-image: /tmp/${charm}_registry.yaml
 
 EOF
     done