In Ubuntu1804 docker image, CI passed before.
However, once glusterfs packages installed, e.g.: glutsterfs-common for deb, glusterfs-devel for rpm, a lot more compile errors appear. Currently I will remove it from dependencies to mute errors, but we need to fix it in future.

Example:
```
 /builds/catalyst-samba/samba/samba-ctdb.stderr <==
In file included from ../../source3/include/includes.h:252:0,
                 from ../../source3/modules/vfs_glusterfs.c:38:
../../source3/modules/vfs_glusterfs.c: In function ‘vfs_gluster_set_volfile_servers’:
../../source3/modules/vfs_glusterfs.c:177:12: error: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘size_t {aka long unsigned int}’ [-Werror=format=]
   DBG_INFO("server %d %s\n", server_count, server);
            ^
../../source3/../lib/util/debug.h:227:15: note: in definition of macro ‘DBG_PREFIX’
   && (dbgtext body) )
               ^~~~
../../source3/modules/vfs_glusterfs.c:177:3: note: in expansion of macro ‘DBG_INFO’
   DBG_INFO("server %d %s\n", server_count, server);
   ^~~~~~~~
../../source3/modules/vfs_glusterfs.c:254:15: error: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘size_t {aka long unsigned int}’ [-Werror=format=]
   DBG_WARNING("Failed to set %d out of %d servers parsed\n",
               ^
        server_count - server_success, server_count);
        ~~~~~~~~~~~~~~~~
../../source3/../lib/util/debug.h:227:15: note: in definition of macro ‘DBG_PREFIX’
   && (dbgtext body) )
               ^~~~
../../source3/modules/vfs_glusterfs.c:254:3: note: in expansion of macro ‘DBG_WARNING’
   DBG_WARNING("Failed to set %d out of %d servers parsed\n",
   ^~~~~~~~~~~
../../source3/modules/vfs_glusterfs.c:254:15: error: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘size_t {aka long unsigned int}’ [-Werror=format=]
   DBG_WARNING("Failed to set %d out of %d servers parsed\n",
               ^
../../source3/../lib/util/debug.h:227:15: note: in definition of macro ‘DBG_PREFIX’
   && (dbgtext body) )
               ^~~~
../../source3/modules/vfs_glusterfs.c:254:3: note: in expansion of macro ‘DBG_WARNING’
   DBG_WARNING("Failed to set %d out of %d servers parsed\n",
   ^~~~~~~~~~~
cc1: all warnings being treated as errors


```