shared/gatt-db: Fix declaration attributes permission

shared/gatt-db: Fix declaration attributes permission

According to Bluetooth Core specification v4.2 (Vol. 3, part G,
section 3.1), service declararion attributes should have only READ
permission. The same obligation has charateristic declaration and
include service declaration attributes.

Without this permission connected clients could corrupt GATT database
by writing to declaration attributes. After thatm service discovery
fails in other clients.

Change-Id: Ib18c4de213e9c242a09a770d9f24cd850a1af6a0
Signed-off-by: Amit Purwar <amit.purwar@samsung.com>