Resume expanding abbreviations for command-line options

The fix for bug 4647 accidentally removed our hack from bug 586 that
rewrote HashedControlPassword to __HashedControlSessionPassword when
it appears on the commandline (which allowed the user to set her own
HashedControlPassword in the torrc file while the controller generates
a fresh session password for each run).

Fixes bug 12948; bugfix on 0.2.5.1-alpha.

changes/bug12948

@@ -0,0 +1,8 @@
+  o Major bugfixes:
+    - Resume expanding abbreviations for command-line options. The fix
+      for bug 4647 accidentally removed our hack from bug 586 that rewrote
+      HashedControlPassword to __HashedControlSessionPassword when it
+      appears on the commandline (which allowed the user to set her
+      own HashedControlPassword in the torrc file while the controller
+      generates a fresh session password for each run). Fixes bug 12948;
+      bugfix on 0.2.5.1-alpha.

src/or/config.c

@@ -1932,7 +1932,8 @@ config_parse_commandline(int argc, char **argv, int ignore_errors,
     }
 
     param = tor_malloc_zero(sizeof(config_line_t));
-    param->key = is_cmdline ? tor_strdup(argv[i]) : tor_strdup(s);
+    param->key = is_cmdline ? tor_strdup(argv[i]) :
+                   tor_strdup(config_expand_abbrev(&options_format, s, 1, 1));
     param->value = arg;
     param->command = command;
     param->next = NULL;