Don't look for weston.ini in the current working directory

It's a bit surprising that Weston looks different when launched from the root
of the git repo vs from elsewhere.

But it's also technically a security vulnerability: if I launch it from
a directory like /tmp, it might pick up a weston.ini created by another user,
which could then load modules with arbitrary code. Basically, it's the same
problem as including "." in $PATH.
Signed-off-by: Dima Ryazanov <dima@gmail.com>

man/weston.ini.man

@@ -27,7 +27,6 @@ server is started:
 .B  "weston/weston.ini in each"
 .BR "\ \ \ \ $XDG_CONFIG_DIR           " "(if $XDG_CONFIG_DIRS is set)"
 .BR "/etc/xdg/weston/weston.ini    " "(if $XDG_CONFIG_DIRS is not set)"
-.BR "<current dir>/weston.ini      " "(if no variables were set)"
 .fi
 .RE
 .PP

man/weston.man

@@ -261,14 +261,12 @@ See
 .SH FILES
 .
 If the environment variable is set, the configuration file is read
-from the respective path, or the current directory if neither is set.
+from the respective path.
 .PP
 .BI $XDG_CONFIG_HOME /weston.ini
 .br
 .BI $HOME /.config/weston.ini
 .br
-.I ./weston.ini
-.br
 .
 .\" ***************************************************************
 .SH ENVIRONMENT

shared/config-parser.c

@@ -75,8 +75,7 @@ open_config_file(struct weston_config *c, const char *name)
 	}
 
 	/* Precedence is given to config files in the home directory,
-	 * and then to directories listed in XDG_CONFIG_DIRS and
-	 * finally to the current working directory. */
+	 * then to directories listed in XDG_CONFIG_DIRS. */
 
 	/* $XDG_CONFIG_HOME */
 	if (config_dir) {
@@ -111,10 +110,7 @@ open_config_file(struct weston_config *c, const char *name)
 			next++;
 	}
 
-	/* Current working directory. */
-	snprintf(c->path, sizeof c->path, "./%s", name);
-
-	return open(c->path, O_RDONLY | O_CLOEXEC);
+	return -1;
 }
 
 static struct weston_config_entry *