Make spec compliant with gbs --incremental

Make spec compliant with gbs --incremental

According to [1], %prep section of the spec file should contain a single
%setup macro, nothing else. According to [2], manifest %files are best
copied to %{buildroot}%{_datadir} in the %install section.

Moved manifest copy operations from %prep to %install accordingly.

References
[1] https://source.tizen.org/documentation/reference/git-build-system/usage/gbs-build
[2] https://wiki.tizen.org/Security/Application_installation_and_Manifest

Change-Id: Ie9b683d8bee96528407aefc04b6bf1981166f559