build: Don't hardcode libtool specific build path

Don't hardcode the libtool specific build path in the configuration
file, but in the build declaration instead.

tests/pam/services/Makefile.am

 all-am: fprintd-pam-test
 
 fprintd-pam-test: fprintd-pam-test.in Makefile
-	sed -e "s|\@TOPBUILDDIR\@|$(abs_top_builddir)|" $< > $@
+	sed -e "s|\@FPRINTDPAMPATH\@|$(abs_top_builddir)/pam/.libs/pam_fprintd.so|" $< > $@
 
 EXTRA_DIST = fprintd-pam-test.in
 CLEANFILES = fprintd-pam-test

tests/pam/services/fprintd-pam-test.in

-auth   required     @TOPBUILDDIR@/pam/.libs/pam_fprintd.so debug timeout=10
+auth   required     @FPRINTDPAMPATH@ debug timeout=10