updater: Output msg when recovery is called

Output messages in log when recovery is attempted or succeeded during
incremental OTA update.

Change-Id: I4033df7ae3aaecbc61921d5337eda26f79164fda
diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index a9d8cc6..9a76a24 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -1659,6 +1659,9 @@
         return StringValue(strdup(""));
     }
 
+    // Output notice to log when recover is attempted
+    fprintf(stderr, "%s image corrupted, attempting to recover...\n", filename->data);
+
     // When opened with O_RDWR, libfec rewrites corrupted blocks when they are read
     fec::io fh(filename->data, O_RDWR);
 
@@ -1709,7 +1712,7 @@
             //     read and check if the errors field value has increased.
         }
     }
-
+    fprintf(stderr, "...%s image recovered successfully.\n", filename->data);
     return StringValue(strdup("t"));
 }