Bug#3274: typo in screen manpage

[eichin@kitten.gen.ma.us (Mark W. Eichin)]

package: screen
version: 3.7.1-4

.SH CUSTOMIZATION
The \*Qsocket directory\*U defaults either to $HOME/.screen or simply to
/tmp/screens or preferably to /usr/local/screens chosen at
compile-time. (/tmp/screen for debian)
               ^^^^^^^^^^^
actually, it is using /tmp/screens...