butc: fix format overflow warning

butc: fix format overflow warning

Recent versions of gcc generate an overflow warning in the butc DUMPNAME macro
when copying values into the finishedMsg1 buffer. Increase the size of the
destination buffer to avoid a possible buffer overflow.

    dump.c:88:24: error: ‘%s’ directive writing up to 63 bytes into
    a region of size 50 [-Werror=format-overflow=]
          sprintf(dumpname, "%s (DumpId %u)", name, dbDumpId);
                            ^
    dump.c:1294:5: note: in expansion of macro ‘DUMPNAME’
         DUMPNAME(finishedMsg1, nodePtr->dumpSetName, dparams.databaseDumpId);
         ^~~~~~~~
    dump.c:88:6: note: ‘sprintf’ output between 12 and 84 bytes into
    a destination of size 50
          sprintf(dumpname, "%s (DumpId %u)", name, dbDumpId);
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    dump.c:1294:5: note: in expansion of macro ‘DUMPNAME’
         DUMPNAME(finishedMsg1, nodePtr->dumpSetName, dparams.databaseDumpId);
         ^~~~~~~~

Reviewed-on: https://gerrit.openafs.org/12916
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit cec45d59440f55316097cfd6652d2ea26cd55233)

Change-Id: I9f3b284d4a32b868091986964af128ed9b3557fd
Reviewed-on: https://gerrit.openafs.org/13097
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>