If dhclient.conf contains the following line send host-name "foobar"; the parsed hostname will be: foobar" (yes, with a trailing quote character). The buggy code is in system-settings/plugins/ifnet/net_utils.c around line 911: strip_string (tmp, '"'); strip_string (tmp, ';'); Basically those two lines need to be swapped, so that the semicolon is _first_ removed and then _both_ quotes are removed.
Fixed in networkmanager-0.8.2-r4.ebuild. Thanks.