do parse defaultlanguage from asterisk.conf

Do parse the option "defaultlanguage" from the [options] section of
asterisk.conf, as in the sample config file. Otherwise the build-time
default language (normally "en") is always the default one.

Review: https://reviewboard.asterisk.org/r/1342/
Signed-off-by: Tzafrir Cohen (License #5035) <tzafrir.cohen@xorcom.com>
Original-Commit: http://svn.digium.com/svn/asterisk/branches/1.8@335716

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@335717 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/asterisk.c

@@ -3055,6 +3055,8 @@ static void ast_readconfig(void)
 			}
 		} else if (!strcasecmp(v->name, "languageprefix")) {
 			ast_language_is_prefix = ast_true(v->value);
+		} else if (!strcasecmp(v->name, "defaultlanguage")) {
+			ast_copy_string(defaultlanguage, v->value, MAX_LANGUAGE);
  		} else if (!strcasecmp(v->name, "lockmode")) {
  			if (!strcasecmp(v->value, "lockfile")) {
  				ast_set_lock_type(AST_LOCK_TYPE_LOCKFILE);