Fix problem with AttributeHeader::init() seen with gcc 4.2.1.

Using the same object as both Uint32 and class AttributeHeader violates
strict aliasing rule.


ndb/include/kernel/AttributeHeader.hpp:
  Fix problem with AttributeHeader::init() seen with gcc 4.2.1.
  
  Using the same object as both Uint32 and class AttributeHeader violates
  strict aliasing rule.
ndb/src/kernel/blocks/dbtup/DbtupExecQuery.cpp:
  Fix problem with AttributeHeader::init() seen with gcc 4.2.1.
  
  Using the same object as both Uint32 and class AttributeHeader violates
  strict aliasing rule.
ndb/src/kernel/blocks/dbtup/DbtupRoutines.cpp:
  Fix problem with AttributeHeader::init() seen with gcc 4.2.1.
  
  Using the same object as both Uint32 and class AttributeHeader violates
  strict aliasing rule.
ndb/src/kernel/blocks/dbutil/DbUtil.cpp:
  Fix problem with AttributeHeader::init() seen with gcc 4.2.1.
  
  Using the same object as both Uint32 and class AttributeHeader violates
  strict aliasing rule.
ndb/src/ndbapi/NdbOperationDefine.cpp:
  Fix problem with AttributeHeader::init() seen with gcc 4.2.1.
  
  Using the same object as both Uint32 and class AttributeHeader violates
  strict aliasing rule.