Make MASK_CANCELLED loadstate + minor log info

Make MASK_CANCELLED loadstate + minor log info

When we remove the image during ApplyMask job,
the loadstate become "CANCELLED".
And, if we re-load the same image,
the loadstate revived as "LOADING".

Without MASK_CANCELLED state, that image will send
ApplyMask one more times.
That mean, alpha mask applied double times.

This patch seperate the cancelled situation
so we can revive the loadstate well.

+

Add some more informations for log

Change-Id: I055bb9807d2c1afe7192daa29aca08cd47910968
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>