build: fix mess with 'db_test_SOURCES' and 'db_test_LDADD'

Somehow both 'db_test_SOURCES' and 'db_test_LDADD' ended up in
'src/Makefile.am'. This causes automake / autoconf to complain.
Let's get rid of both useless declarations.

Furthermore, the actual 'db_test_LDADD' in 'tests/Makefile.am'
contained references to the source files from '$(top_srcdir)'.
Most likely, the original intention was to depend on the object
files in '$(top_builddir)'. Let's also fix this.

Change-Id: Ib2e436ed91d9b7551dc5b205329d468c2b0ced04
2 files changed