Add support for .bss section in oat files.

Change-Id: I779b80b8139d9afdc28373f8c68edff5df7726ce
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 8411091..c32a992 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -403,6 +403,7 @@
     image_writer_(image_writer),
     dex_files_(&dex_files),
     size_(0u),
+    bss_size_(0u),
     oat_data_offset_(0u),
     image_file_location_oat_checksum_(image_file_location_oat_checksum),
     image_file_location_oat_begin_(image_file_location_oat_begin),