symlink-cache: remove from the build

symlink-cache was written as an experiment to reduce the load
on 'build' systems, which keep doing symlink resolution to get
the proper header files. But since last 6+ years, there was no
way to add it to the volfile using gluster cli, and hence was
not supported anymore. As it is not maintained, and as announced
on [1], we are planning to remove it from the build system.

[1]- https://lists.gluster.org/pipermail/gluster-users/2018-July/034400.html

updates: bz#1635688
Change-Id: Iaa25069bceed04cf65f79a4b4a02c05cee848eb5
Signed-off-by: Amar Tumballi <amarts@redhat.com>

configure.ac

@@ -81,8 +81,6 @@ AC_CONFIG_FILES([Makefile
                 xlators/performance/io-threads/src/Makefile
                 xlators/performance/io-cache/Makefile
                 xlators/performance/io-cache/src/Makefile
-                xlators/performance/symlink-cache/Makefile
-                xlators/performance/symlink-cache/src/Makefile
                 xlators/performance/quick-read/Makefile
                 xlators/performance/quick-read/src/Makefile
                 xlators/performance/open-behind/Makefile

glusterfs.spec.in

@@ -1112,9 +1112,6 @@ exit 0
      %{_libdir}/glusterfs/%{version}%{?prereltag}/xlator/features/quiesce.so
 %dir %{_libdir}/glusterfs/%{version}%{?prereltag}/xlator/playground
      %{_libdir}/glusterfs/%{version}%{?prereltag}/xlator/playground/template.so
-%dir %{_libdir}/glusterfs/%{version}%{?prereltag}/xlator/testing
-%dir %{_libdir}/glusterfs/%{version}%{?prereltag}/xlator/testing/performance
-     %{_libdir}/glusterfs/%{version}%{?prereltag}/xlator/testing/performance/symlink-cache.so
 
 %files fuse
 # glusterfs is a symlink to glusterfsd, -server depends on -fuse.

xlators/performance/Makefile.am

@@ -1,4 +1,4 @@
 SUBDIRS = write-behind read-ahead readdir-ahead io-threads io-cache \
-	symlink-cache quick-read md-cache open-behind decompounder nl-cache
+	quick-read md-cache open-behind decompounder nl-cache
 
 CLEANFILES =