common parts of libmysql.c and sql/mini_client.cc moved to sql-common/client.c
names of functions now are same in both cases


libmysql/libmysql.c:
  many parts moved to sql-common/client.c
libmysqld/Makefile.am:
  superfluous files removed
sql/mini_client.cc:
  most of the file moved to sql-common/client.c
sql/mini_client.h:
  mc_ prefixes were deleted
sql/repl_failsafe.cc:
  mc_ prefixes removed
sql/slave.cc:
  _mc prefixes removed