Correct phase count on mysql_upgrade

Add static vars on phases to make merging consistent.

client/mysql_upgrade --verbose -S /tmp/s.sock
Looking for 'mysql' as: client/mysql
Looking for 'mysqlcheck' as: client/mysqlcheck
Phase 1/4: Fixing views - skipped - not required
Phase 2/4: Fixing table and database names
Processing databases
information_schema
mysql
performance_schema
test
Phase 3/4: Checking and upgrading tables
Processing databases
information_schema
mysql
mysql.columns_priv                                 OK
mysql.db                                           OK
mysql.event                                        OK
mysql.func                                         OK
mysql.help_category                                OK
mysql.help_keyword                                 OK
mysql.help_relation                                OK
mysql.help_topic                                   OK
mysql.host                                         OK
mysql.ndb_binlog_index                             OK
mysql.plugin                                       OK
mysql.proc                                         OK
mysql.procs_priv                                   OK
mysql.proxies_priv                                 OK
mysql.servers                                      OK
mysql.tables_priv                                  OK
mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK
performance_schema
test
Phase 4/4: Running 'mysql_fix_privilege_tables'...
OK

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