javac ast indices: remove redundant log.info

jps/jps-builders/src/org/jetbrains/jps/backwardRefs/CompilerBackwardReferenceIndex.java

@@ -167,8 +167,7 @@ public class CompilerBackwardReferenceIndex {
         is.close();
       }
     }
-    catch (IOException ex) {
-      LOG.info(ex);
+    catch (IOException ignored) {
     }
     return true;
   }