Revert "Update man page for new UseBridges tristate behaviour."

This reverts commit 40cfad1b5ae90b06eb74861a4fdc1310f8611111.

doc/tor.1.txt

@@ -708,14 +708,10 @@ The following options are useful only for clients (that is, if
     from the configured bridge authorities when feasible. It will fall back to
     a direct request if the authority responds with a 404. (Default: 0)
 
-**UseBridges** **0**|**1**|**auto**::
-    Make Tor fetch descriptors for each bridge listed in the "Bridge"
+**UseBridges** **0**|**1**::
+    When set, Tor will fetch descriptors for each bridge listed in the "Bridge"
     config lines, and use these relays as both entry guards and directory
-    guards. If the option is 1, bridges must be used and if no bridges are
-    configured Tor will not make any connections until a bridge is configured;
-    if it's "auto", Tor will use bridges if any are configured, otherwise it
-    will connect directly to the Tor network; if it's 0, bridges are not used
-    at all. (Defaults to auto)
+    guards. (Default: 0)
 
 **UseEntryGuards** **0**|**1**::
     If this option is set to 1, we pick a few long-term entry servers, and try