Add two new configure options that specify:
1. when to add padding to the openib control header - this *only* happens when the configure option is specified
2. when to use the dr-like checksum as opposed to the memcpy checksum. Not selectable at runtime - to eliminate performance impacts, this is a configure-only option
Also removed an unused checksum version from opal/util/crc.h.
The new component still needs a little cleanup and some sync with recent ob1 bug fixes. It was created as a separate module to avoid performance hits in ob1 itself, though most of the code is duplicative. The component is only selectable by either specifying it directly, or configuring with the dr-like checksum -and- setting -mca pml_csum_enable_checksum 1.
Modify the LANL platform files to take advantage of the new module.
This commit was SVN r20846.
