Generate a fatal error as appropriate.

Otherwise, subdirectories under directories which are added to
a resource file generate garbage in the binary.

The easiest way to see this is

 cd tests/auto/corelib/kernel/qvariant
 mkdir stream/qt4.9/somedir
 make && ./tst_qvariant loadQt4Stream

Change-Id: I32630ecb6d515db1d135f0ffc5cf14fd8caa0a4f
Reviewed-by: hjk <qthjk@ovi.com>

src/tools/rcc/rcc.cpp

@@ -835,8 +835,10 @@ bool RCCResourceLibrary::writeDataBlobs()
                 pending.push(child);
             else {
                 offset = child->writeDataBlob(*this, offset, &errorMessage);
-                if (offset == 0)
+                if (offset == 0) {
                     m_errorDevice->write(errorMessage.toUtf8());
+                    return false;
+                }
             }
         }
     }