upgrade from <=5.0.46 to >=5.0.48

Problem: 'check table .. for upgrade' doesn't detect 
incompatible collation changes made in 5.0.48.

Fix: check for incompatible collation changes.


sql/handler.cc:
  Fix for bug#39585: innodb and myisam corruption after binary 
  upgrade from <=5.0.46 to >=5.0.48
    - check for incompatible collation changes made in 5.0.48:
  bug #29461
    latin7_general_ci
    latin7_general_cs
    latin7_estonian_cs
    latin2_hungarian_ci
    koi8u_general_ci
    cp1251_ukrainian_ci
    cp1250_general_ci
  bug #29499, bug #27562
    ascii_general_ci