Log correctly on owner/user mismatch.

Found with clang's scan-build while looking at dead assignments.

Fixes bug 23487; bugfix on 1135405c8c6ea31 in 0.2.9.1-alpha

changes/bug23487

@@ -0,0 +1,5 @@
+  o Minor bugfixes (logging):
+    - When warning about a directory owned by the wrong user, log the actual
+      name of the user owning the directory.  Previously, we'd log the name
+      of the process owner twice. Fixes bug 23487; bugfix on 0.2.9.1-alpha.
+

src/common/util.c

@@ -2334,8 +2334,8 @@ check_private_dir,(const char *dirname, cpd_check_t check,
 
     log_warn(LD_FS, "%s is not owned by this user (%s, %d) but by "
         "%s (%d). Perhaps you are running Tor as the wrong user?",
-                         dirname, process_ownername, (int)running_uid,
-                         pw ? pw->pw_name : "<unknown>", (int)st.st_uid);
+             dirname, process_ownername, (int)running_uid,
+             pw_uid ? pw_uid->pw_name : "<unknown>", (int)st.st_uid);
 
     tor_free(process_ownername);
     close(fd);