cachemgr store file too big error exit via usual path

cachemgr store file too big error exit via usual path

have just one path for exiting on errors so we do everything

this means we will EndCall, instead of not, in the EFBIG case

Change-Id: I2df025eee4bd5173ed4f80a73f9a9a347e7257d2
Reviewed-on: http://gerrit.openafs.org/1827
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>