configure: Remove --enable-test-coverage

We provide a custom configure option --enable-test-coverage and
'make cov' target to generate code coverage reports. However gnulib
already provides a 'make coverage' which 'just works' and doesn't
require a special configure option.

This drops our custom implementation in favor of 'make coverage'.
Reports are now output to cov/index.html

Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>

Makefile.am

@@ -16,15 +16,15 @@
 ## License along with this library.  If not, see
 ## <http://www.gnu.org/licenses/>.
 
-LCOV = lcov
-GENHTML = genhtml
-
 SUBDIRS = . gnulib/lib include/libvirt src tools docs gnulib/tests \
   tests po examples
 
 XZ_OPT ?= -v -T0
 export XZ_OPT
 
+# have gnulib 'make coverage' output to 'cov' dir
+COVERAGE_OUT = "cov"
+
 ACLOCAL_AMFLAGS = -I m4
 
 EXTRA_DIST = \
@@ -77,20 +77,6 @@ check-local: all tests
 check-access:
 	@($(MAKE) $(AM_MAKEFLAGS) -C tests check-access)
 
-cov: clean-cov
-	$(MKDIR_P) $(top_builddir)/coverage
-	$(LCOV) -c -o $(top_builddir)/coverage/libvirt.info.tmp \
-	  -d $(top_builddir)/src \
-	  -d $(top_builddir)/tests
-	$(LCOV) -r $(top_builddir)/coverage/libvirt.info.tmp \
-	  -o $(top_builddir)/coverage/libvirt.info
-	rm $(top_builddir)/coverage/libvirt.info.tmp
-	$(GENHTML) --show-details -t "libvirt" -o $(top_builddir)/coverage \
-	  --legend $(top_builddir)/coverage/libvirt.info
-
-clean-cov:
-	rm -rf $(top_builddir)/coverage
-
 MAINTAINERCLEANFILES = .git-module-status
 
 dist-hook: gen-ChangeLog gen-AUTHORS