adapt to BCEL change, see dist-ant's Gump build failure

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@827887 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/util/depend/bcel/AncestorAnalyzer.java

@@ -23,6 +23,7 @@ import java.util.Hashtable;
 import java.util.Vector;
 import org.apache.bcel.classfile.ClassParser;
 import org.apache.bcel.classfile.JavaClass;
+import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.util.depend.AbstractAnalyzer;
 
 /**
@@ -42,8 +43,13 @@ public class AncestorAnalyzer extends AbstractAnalyzer {
         // force BCEL classes to load now
         try {
             new ClassParser("force");
-        } catch (IOException e) {
-            // ignore
+        } catch (Exception e) {
+            // all released versions of BCEL may throw an IOException
+            // here, but BCEL's trunk does no longer declare to do so
+            if (!(e instanceof IOException)) {
+                throw new BuildException(e);
+            }
+            // ignore IOException like we've always done
         }
     }