Reduce the severity of the msg related to 'cache missed'
when the export list cache was access the very first time.

Signed-off-by: Rong Zeng <rongzeng@us.ibm.com>
Added handling of EUNATCH from GPFS

Signed-off-by: Venkateswararao Jujjuri (JV) <jvrao@linux.vnet.ibm.com>
Signed-off-by: Rong Zeng <rongzeng@us.ibm.com>