MSAN use-of-uninitialized-value in wsrep_xid_print

==418706==WARNING: MemorySanitizer: use-of-uninitialized-value

    #0 0x5596c8b569b6 in wsrep_xid_print(xid_t const*) /source/sql/wsrep_xid.cc:257:56

    #1 0x5596c8b555eb in get_SE_checkpoint(THD*, st_plugin_int*, void*) /source/sql/wsrep_xid.cc:151:5

    #2 0x5596c7af7ee1 in plugin_foreach_with_mask(THD*, char (*)(THD*, st_plugin_int*, void*), int, unsigned int, void*) /source/sql/sql_plugin.cc:2558:15

    #3 0x5596c8b55dab in wsrep_get_SE_checkpoint(xid_t&) /source/sql/wsrep_xid.cc:158:10

    #4 0x5596c8b55dab in wsrep_get_SE_checkpoint_common(xid_t&) /source/sql/wsrep_xid.cc:166:7

    #5 0x5596c8b5609b in wsrep_server_gtid_t wsrep_get_SE_checkpoint<wsrep_server_gtid_t>() /source/sql/wsrep_xid.cc:204:8

    #6 0x5596c8b60ae5 in wsrep_init_gtid() /source/sql/wsrep_mysqld.cc:368:36

    #7 0x5596c8b60ae5 in wsrep_init_globals() /source/sql/wsrep_mysqld.cc:830:3

    #8 0x5596c7722d2a in mysqld_main(int, char**) /source/sql/mysqld.cc:5946:7

    #9 0x7f68e5b73ca7  (/lib/x86_64-linux-gnu/libc.so.6+0x29ca7) (BuildId: def5460e3cee00bfee25b429c97bcc4853e5b3a8)

    #10 0x7f68e5b73d64 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29d64) (BuildId: def5460e3cee00bfee25b429c97bcc4853e5b3a8)

    #11 0x5596c767bf60 in _start (/build/sql/mariadbd+0x7b8f60) (BuildId: b5916fdc43d36775ed295ebd724239356f70cf34)

  Uninitialized value was created by an allocation of 'xid' in the stack frame

    #0 0x5596c8b56093 in wsrep_server_gtid_t wsrep_get_SE_checkpoint<wsrep_server_gtid_t>() /source/sql/wsrep_xid.cc:201:3

SUMMARY: MemorySanitizer: use-of-uninitialized-value /source/sql/wsrep_xid.cc:257:56 in wsrep_xid_print(xid_t const*)