Refs #8: preserve gvwstate.dat for pc recovery feature

scripts/wsrep_sst_xtrabackup-v2.sh

@@ -282,7 +282,7 @@ read_cnf()
     progress=$(parse_cnf sst progress "")
     rebuild=$(parse_cnf sst rebuild 0)
     ttime=$(parse_cnf sst time 0)
-    cpat=$(parse_cnf sst cpat '.*galera\.cache$\|.*sst_in_progress$\|.*grastate\.dat$\|.*\.err$\|.*\.log$\|.*RPM_UPGRADE_MARKER$\|.*RPM_UPGRADE_HISTORY$')
+    cpat=$(parse_cnf sst cpat '.*galera\.cache$\|.*sst_in_progress$\|.*grastate\.dat$\|.*gvwstate\.dat$\|.*\.err$\|.*\.log$\|.*RPM_UPGRADE_MARKER$\|.*RPM_UPGRADE_HISTORY$')
     incremental=$(parse_cnf sst incremental 0)
     ealgo=$(parse_cnf xtrabackup encrypt "")
     ekey=$(parse_cnf xtrabackup encrypt-key "")