Fix C code naming rules & minor fixes

Fix C code naming rules & minor fixes

- Remove some goto label which isn't needed
- Change 'num' param of strncmp / strncpy with meaningful value
  (static buffer's size)
- Add const to unsigned char array input param
- Change param names (c string array and raw buffer array)
  const char *pPkgId -> pkgId
  unsigned char *pDek -> dek
  unsigned char **ppDek -> pDek
- Change all camel naminges to underbar
- Remove null checking before call free()
  free() does nothing if ptr is null pointer.
  (refer: http://linux.die.net/man/3/free)
- Add missing closedir() after opendir()

Change-Id: I7e5888ed3dc77e5355cfc441f10dc0d6d916921c
Signed-off-by: Kyungwook Tak <k.tak@samsung.com>