Fix a regression in parsing descriptors.

CHANGELOG.md

-# Changes in version 1.9.0 - 2017-06-??
+# Changes in version 1.8.2 - 2017-06-16
+
+ * Medium changes
+   - Fix a regression where any DescriptorParseException thrown while
+     parsing a descriptor is encapsulated and rethrown as
+     RuntimeException.
 
 
 # Changes in version 1.8.1 - 2017-06-08

src/main/java/org/torproject/descriptor/impl/DescriptorParserImpl.java

@@ -195,9 +195,15 @@ public class DescriptorParserImpl implements DescriptorParser {
     try {
       return constructor.newInstance(rawDescriptorBytes,
           offsetAndLength, failUnrecognizedDescriptorLines);
-    } catch (InstantiationException | IllegalAccessException
-        | InvocationTargetException e) {
-      throw new RuntimeException();
+    } catch (InvocationTargetException e) {
+      if (null != e.getCause()
+          && e.getCause() instanceof DescriptorParseException) {
+        throw (DescriptorParseException) e.getCause();
+      } else {
+        throw new RuntimeException(e);
+      }
+    } catch (InstantiationException | IllegalAccessException e) {
+      throw new RuntimeException(e);
     }
   }