Remove unused catch

Author: renefloor

cached_network_image/lib/src/image_provider/_image_loader.dart

@@ -125,7 +125,7 @@ class ImageLoader implements platform.ImageLoader {
           yield decoded;
         }
       }
-    } on Object catch (e) {
+    } on Object {
       // Depending on where the exception was thrown, the image cache may not
       // have had a chance to track the key in the cache at all.
       // Schedule a microtask to give the cache a chance to add the key.

cached_network_image_web/lib/cached_network_image_web.dart

@@ -137,7 +137,7 @@ class ImageLoader implements platform.ImageLoader {
           yield decoded;
         }
       }
-    } on Object catch (e) {
+    } on Object {
       // Depending on where the exception was thrown, the image cache may not
       // have had a chance to track the key in the cache at all.
       // Schedule a microtask to give the cache a chance to add the key.