shortcut: release pressed keys before input H/W keycode
when user input shortcut key,
the last key sequence is replaced with H/W keycode.
So the key combination on guest is twisted.
Here is an example.
This is key sequence of Menu H/W key: "Crtl + Shift + F6"
If user press "F6",
this key is not delivered to guest but "keycode 169" is delivered.
Finally guest gets "Ctrl + Shift" and "keycode 169".
It occurs unexpected behavior on guest side.
So, if user want to input H/W keycode with shortcut,
all keys pressed should be released before send it.
Change-Id: I82e1310af577d1ab43d20e2f5a9362ba2f58e59c
Signed-off-by: Munkyu Im <munkyu.im@samsung.com>