Add missing field init in constructors

Adds missing field initializations detected by Eclipse IDE.

Change-Id: I5f2f32bcccb12545fc9f0b42fcec74a23dc81376
diff --git a/runtime/image.h b/runtime/image.h
index 1a0d8fd..e2d59f9 100644
--- a/runtime/image.h
+++ b/runtime/image.h
@@ -78,7 +78,10 @@
 // header of image files written by ImageWriter, read and validated by Space.
 class PACKED(4) ImageHeader {
  public:
-  ImageHeader() : compile_pic_(0) {}
+  ImageHeader()
+      : image_begin_(0U), image_size_(0U), oat_checksum_(0U), oat_file_begin_(0U),
+        oat_data_begin_(0U), oat_data_end_(0U), oat_file_end_(0U), patch_delta_(0),
+        image_roots_(0U), pointer_size_(0U), compile_pic_(0) {}
 
   ImageHeader(uint32_t image_begin,
               uint32_t image_size_,