Fix warnings from afsconf_SetExtendedCellInfo

Fix warnings from afsconf_SetExtendedCellInfo

If a is declared as an array, then a == &a. However, the compiler
still gives a type warning when usign the & form, as the types no
longer match. 5f720faab920a1007327de415ceaf187c16fdbe6 fixed this
problem for calls to GetExtendedCellInfo - do the same for the
corresponding Set calls.

Change-Id: I8204afe7df0c0db1d059cb3f6ab61eff1cdf9140
Reviewed-on: http://gerrit.openafs.org/808
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>