BUG#18962: DROP PARTITION fails when partitions dropped for subpartitions with default naming procedure
Fixed naming procedures for default partitioning and default subpartitioning


mysql-test/r/partition_pruning.result:
  Fixed test cases for new naming of default subpartitions
mysql-test/r/partition_range.result:
  New test case
mysql-test/t/partition_range.test:
  New test case
sql/partition_info.cc:
  Fixed naming procedures for default partitioning and default subpartitioning
sql/partition_info.h:
  Fixed naming procedures for default partitioning and default subpartitioning