[IOT-1076] Added missed file/cbor-handling bug-fix(s) on |psinterface.c|

[IOT-1076] Added missed file/cbor-handling bug-fix(s) on |psinterface.c|

this change mainly includes as the following:
- persistent storage close after using svr-db
- moved or removed overlapped variables into its scope
- added missed error-handling codes and so on

[patch #1] initial commit
[patch #2] updated commit message
[patch #3-4] aligned iotivity coding guide

Jira: https://jira.iotivity.org/browse/IOT-1076

Change-Id: Ib39dddb3ca428fbf856c1abf3d45f6b855460d73
Signed-off-by: Kyungsun Cho <goodsun.cho@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/7617
Reviewed-by: Ashwini  Kumar <k.ashwini@samsung.com>
Reviewed-by: Chul Lee <chuls.lee@samsung.com>
Reviewed-by: Yonggoo Kang <ygace.kang@samsung.com>
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jongsung Lee <js126.lee@samsung.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>