Print size as unsigned when sending to framework.

Otherwise we might output negative numbers that confuse the rest
of the recovery stack.

Bug: 26007445
Change-Id: Ic99b49360732e5389c6330be065e1222e25b60ca

Disk.cpp

@@ -236,7 +236,7 @@ status_t Disk::readMetadata() {
     }
     }
 
-    notifyEvent(ResponseCode::DiskSizeChanged, StringPrintf("%" PRId64, mSize));
+    notifyEvent(ResponseCode::DiskSizeChanged, StringPrintf("%" PRIu64, mSize));
     notifyEvent(ResponseCode::DiskLabelChanged, mLabel);
     notifyEvent(ResponseCode::DiskSysPathChanged, mSysPath);
     return OK;