improve SurfaceFlinger 'dumpsys' log

list the purgatory, which shows windows that have been closed,
but for which the client still has references.

Change-Id: I5168bb88cb328d5d77d71d0871deb9190f493126
diff --git a/libs/ui/GraphicBufferAllocator.cpp b/libs/ui/GraphicBufferAllocator.cpp
index ce84683..33ef1fc 100644
--- a/libs/ui/GraphicBufferAllocator.cpp
+++ b/libs/ui/GraphicBufferAllocator.cpp
@@ -61,7 +61,7 @@
     const size_t c = list.size();
     for (size_t i=0 ; i<c ; i++) {
         const alloc_rec_t& rec(list.valueAt(i));
-        snprintf(buffer, SIZE, "%10p: %7.2f KiB | %4u (%4u) x %4u | %2d | 0x%08x\n",
+        snprintf(buffer, SIZE, "%10p: %7.2f KiB | %4u (%4u) x %4u | %8X | 0x%08x\n",
             list.keyAt(i), rec.size/1024.0f, 
             rec.w, rec.s, rec.h, rec.format, rec.usage);
         result.append(buffer);