SAP: Fix missing attribute in disconnect_ind

The internal TEST flag was removing too much code.
To make it easier to run test, and avoid future issues
with removing needed code, the TEST flag is no longer used
to remove code.

This bug was noticed when running the PTS testcases without the
PTS_TEST flag set. It is assumed that this fix will make
TC_SERVER_DCN_BV_02_I work without the PTS flag, but unless PTS
have updated their test case to accept both a gracefull disconnect
and a forced disconnect, TC_SERVER_DCN_BV_03_I will still fail in
a production build. The SAP spec suggest to use a gracefull disconnect
when initiating a disconnect from a server, hence it is not a good
idea to expose a force disconnect option to the used without first
having tried a gracefull disconnect. Hence the PTS test case
implementation is in conflict with the intented use specified in
the SAP specification.

Without this fix a build with PTS_TEST=false will not work as
intented.

PTS_TEST replaced with system property bt.sap.pts. Set it to true
to enable the force disconnect button.

Bug: 23614694
Signed-off-by: Casper Bonde <c.bonde@samsung.com>
Change-Id: I776a53d6e786c21000ef62094f9a9948ee5880b8