cmake: align cmake names of library packages

cmake: align cmake names of library packages

The cmake package names of libraries are case-sensitive. The name used in
FIND_PACKAGE_HANDLE_STANDARD_ARGS - e.g. "cryptopp" - must match the name used
in the module name - "Findcryptopp.cmake" - as well as the name used in
find_package() call - "find_package(cryptopp REQUIRED)"

Note that the term "package" here refers to a cmake abstraction, *not* an
actual RPM or Debian package.

Fixes: http://tracker.ceph.com/issues/19853
Signed-off-by: Nathan Cutler <ncutler@suse.com>