storage: avoid use of undefined GLUSTER_CLI variable

Previous commit tried to change configure logic such that the
GLUSTER_CLI parameter would always be set:

  commit 9e97c8c0
  Author: Peter Krempa <pkrempa@redhat.com>
  Date:   Mon Jan 9 15:56:12 2017 +0100

    storage: gluster: Remove build-time dependency on the 'gluster' cli tool

This missed the fact that the AC_PATH_PROG call was itself inside an 'if'
conditional that would not be called in with_storage_gluster was false. As
a result, GLUSTER_CLI was still conditionally defined.

Just kill the GLUSTER_CLI parameter and AC_PATH_PROG call entirely and pass a
bare "gluster" string to virFindFileInPath instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

configure.ac

@@ -603,15 +603,6 @@ LIBVIRT_STORAGE_CHECK_SHEEPDOG
 LIBVIRT_STORAGE_CHECK_GLUSTER
 LIBVIRT_STORAGE_CHECK_ZFS
 
-if test "$with_storage_fs" = "yes" ||
-   test "$with_storage_gluster" = "yes"; then
-  AC_PATH_PROG([GLUSTER_CLI], [gluster], [gluster], [$LIBVIRT_SBIN_PATH])
-  if test "x$GLUSTER_CLI" != "x"; then
-      AC_DEFINE_UNQUOTED([GLUSTER_CLI], ["$GLUSTER_CLI"],
-        [Location or name of the gluster command line tool])
-  fi
-fi
-
 with_storage=no
 for backend in dir fs lvm iscsi scsi mpath rbd disk; do
     if eval test \$with_storage_$backend = yes; then

src/storage/storage_util.c

@@ -2437,7 +2437,7 @@ virStorageBackendFindGlusterPoolSources(const char *host,
 
     int ret = -1;
 
-    if (!(glusterpath = virFindFileInPath(GLUSTER_CLI))) {
+    if (!(glusterpath = virFindFileInPath("gluster"))) {
         if (report) {
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                            _("'gluster' command line tool not found"));