add judgement to avoid NULL pointer's operation(segmentaion fault)

into  dev3-76.dev.cn.tlan:/home/dli/mysql/mysql-5.0/mysql-5.0-bug-21345

into  dev3-76.dev.cn.tlan:/home/dli/mysql/mysql-5.0/mysql-5.0-ndb-bj

into  dev3-127.(none):/mnt/mysql/home/ngb/bug19873

into  dev3-127.(none):/mnt/mysql/home/ngb/mysql-5.0-ndb-bj

into  dev3-76.dev.cn.tlan:/home/dli/mysql/mysql-5.0/mysql-5.0-bug-21345

Fixed the cluster logfile rotation code, let the cluster log file be renamed correctly when the main log file exceeds the configured maximum size.

into  perch.ndb.mysql.com:/home/jonas/src/mysql-5.0-ndb

into  perch.ndb.mysql.com:/home/jonas/src/mysql-5.0-ndb

into  salvation.intern.azundris.com:/home/tnurnberg/work/mysql-5.0-maint-20987

into  salvation.intern.azundris.com:/home/tnurnberg/work/mysql-5.0-maint-20987

into  zippy.cornsilk.net:/home/cmiller/work/mysql/merge/mysql-5.0

into  orca.ndb.mysql.com:/export/home/space/pekka/ndb/version/my50-bug21017

into  salvation.intern.azundris.com:/home/tnurnberg/work/mysql-5.0-maint-20411

when X.509 subject was required for a connect, we tested whether it was the right
one, but did not refuse the connexion if not. fixed.

(corrected CS now --replace_results socket-path)

into  salvation.intern.azundris.com:/home/tnurnberg/work/mysql-5.0-maint-20987

into  orca.ndb.mysql.com:/export/home/space/pekka/ndb/version/my50-ndb

into  shellback.(none):/home/msvensson/mysql/mysql-5.0-maint

into  hasky.mysql.fi:/home/jani/mysql-5.0_bug21537

into  mysql.com:/home/cps/mysql/trees/mysql-5.0-virgin

innodb r719

into  dev3-76.dev.cn.tlan:/home/lisj/mysql/mysql-5.0/mysql-5.0-ndb-bj

into  zippy.cornsilk.net:/home/cmiller/work/mysql/merge/mysql-5.0

into  zippy.cornsilk.net:/home/cmiller/work/mysql/merge/mysql-5.0

into  zippy.cornsilk.net:/home/cmiller/work/mysql/merge/mysql-5.0

into  zippy.cornsilk.net:/home/cmiller/work/mysql/merge/mysql-5.0

into  zippy.cornsilk.net:/home/cmiller/work/mysql/merge/mysql-5.0

into  rolltop.ignatz42.dyndns.org:/mnt/storeage/mysql-5.0-merge

into  rolltop.ignatz42.dyndns.org:/mnt/storeage/mysql-5.0-maint_20328

These variables must be defined for Netware, or it fails
to recognize hard paths starting from the device.

into  bk-internal.mysql.com:/data0/bk/mysql-5.0-kt