e_policy_visibility: modify code to consider the child's launch cancel while waiting...

e_policy_visibility: modify code to consider the child's launch cancel while waiting uniconify of child

If the child window is to be hidden (by visibility) while the parent window is waiting for uniconify of child window,
then the uniconify_render timeout is occurred because the parent cannot get the "e,action,launch,done" signal of the child window.
So, we add "e,action,launch,cancel" signal event and use this to prevent the timeout of above case.

Change-Id: I97145aab138ce0485767c90836805ade10704415