Run tests in parallel by default on Fedora

An option to enable parallel test runs was added in 6dc6285 ("Improve
test suite coverage", 2017-11-10).  After further improvements it seems
to be reliable for use in koji builds.

It is still disabled for EPEL builds because make lacks support for the
-O (--output-sync) option.  Without this option the output is much less
readable.

In the future we may be able to move to using 'prove' as the default
test harness which might allow us to run in parallel without requiring
the -O option.

git.spec

@@ -44,16 +44,11 @@
 %global test_links 0
 %endif
 
-# Allow tests to run in parallel.  Disabled by default due to unresolved
-# failures when building in koji.  Enabling it speeds up the test suite quite a
-# bit though.  The -O (--output-sync) option requires make > 4.0, which is not
-# available on EL <= 7.  Without it, running the tests in parallel causes the
-# output to be rather unweildy, so restrict parallel tests to Fedora.
-#
-# Pass "--with parallel_tests" or "--define 'parallel_tests 1'" to
-# rpmbuild/mock.
-%bcond_with parallel_tests
-%if %{with parallel_tests} && 0%{?fedora}
+# Run tests in parallel.  This speeds up the test suite quite a bit.  The
+# -O (--output-sync) option requires make > 4.0, which is not available on
+# EL <= 7.  Without it, running the tests in parallel causes the output to
+# be rather unweildy, so restrict parallel tests to Fedora.
+%if 0%{?fedora}
 %global make_test_opts -O %{?_smp_mflags}
 %endif
 
@@ -805,6 +800,7 @@ rm -rf %{buildroot}
 - Fix builds using '--without docs'
 - Mark git-core-docs sub-package noarch
 - Avoid failures in svnserve tests when run in parallel
+- Run tests in parallel by default on Fedora
 
 * Wed Nov 29 2017 Todd Zullinger <tmz@pobox.com> - 2.15.1-2
 - Fix debuginfo for gnome-keyring and libsecret credential helpers