Backport from 6.0

Changed error message to show that it is partitioning
that does not support foreign keys yet.

Changed spelling from British english to American english.

mysql-test/r/partition.result:
  Bug#36001: Partitions: spelling and using some error messages
  
  Backport from 6.0
  
  Changed spelling from British english to American english.
mysql-test/r/partition_mgm_err.result:
  Bug#36001: Partitions: spelling and using some error messages
  
  Backport from 6.0
  
  Changed spelling from British english to American english.
mysql-test/t/partition.test:
  Bug#36001: Partitions: spelling and using some error messages
  
  Backport from 6.0
  
  Added test for verifying error message
sql/share/errmsg.txt:
  Bug#36001: Partitions: spelling and using some error messages
  
  Backport from 6.0
  
  Changed spelling from British english to American english.
sql/sql_table.cc:
  Bug#36001: Partitions: spelling and using some error messages
  
  Backport from 6.0
  
  Using a better error message.