update debian packaging: bump standards version, build-depends on lsb-release, add enhances: mysql-server
sync packaging with Debian
Bug #1255019: Multiple portability issues in archived logs test

Replaced unnecessary linuxisms with portable alternatives. Also removed
the redundant check for xtrabackup_56.
Bug #1223716: innobackupex --help and --version doesn't work if source
              destination isn't specifed

Fixed innobackupex to not fail with an error when --help or --version
are specified on the command line and the target directory argument is
missing.
Bug #1248331: innobackupex error with ANSI_QUOTES sql_mode

Replaced double quotes with single ones in the SQL statement issued by
detect_mysql_capabilities_for_backup().
Merged lp:~stewart/percona-xtrabackup/deb-2.1.6-3.
Merged lp:~akopytov/percona-xtrabackup/bug1255019-2.1.
Merged lp:~akopytov/percona-xtrabackup/bug1223716-2.1.
Merged lp:~akopytov/percona-xtrabackup/bug1248331-2.1.
Bug #1268325: Unstable bug1037379.sh 

Avoid grepping $OUTFILE to detect errors. This is unreliable as output
from multiple processes writing to the same file may be garbled.
Merged lp:~akopytov/percona-xtrabackup/bug1268325-2.1.