Fix bugs on upgrade script

Fix bugs on upgrade script

- Signature file has removed by previous platform for security purpose
  so there are no way to determine privilege level while upgrading.
- So, now upgrade script will make file which stores root cert value
  each package and installer will retrieve it at runtime when there are
  no signature file to read.
- After migration, cert db will be migrated directly into pkg cert db.
- Remove chsmack in script.
- Now tpk related functions will handle rpm packages, too.

Change-Id: I2ec688c94876c903e82274a2eefd63290514578b
Signed-off-by: Junghyun Yeon <jungh.yeon@samsung.com>