Consistently use BZip2 in CMake code instead of BZIP2

Podhorszki, Norbertrequested to merge
github/fork/KyleFromKitware/bzip2-fix into master

Created by: KyleFromKitware

Other parts of the code use ADIOS_HAVE_BZip2, and this inconsistency was causing installation failures. Fix the usage to make it consistent.

Merge request reports