adds support for mounting with 'net use' and 'Map Network Drive'
if we don't have extended attributes on mount (i.e. not using nfs_mount), don't fail! instead, use SrvName=SrvCallName and MntPt=""
updated nfs41_MountConfig_InitDefaults() to initialize SrvName and MntPt with Length=0
Signed-off-by: Casey Bodley <cbodley@umich.edu>