Comment 6 for bug 794749

The attached patch backs out most of the changes made to caget.c in commit 12112 which were causing this problem and at least one other bug. This implements the support for variable length arrays correctly:

* ppv->nElems always holds the array count as reported by ca_element_count()
* ppv->reqElems is set differently if making a ca_get_callback()
* ppv->reqElems is adjusted by the callback routine to the actual array size received

It's easier to follow these changes by comparing the resulting code against rev 12111.