gitweb: Die if there are parsing errors in config file

Otherwise the errors can propagate, and show in damnest places, and
you would spend your time chasing ghosts instead of debugging real
problem (yes, it is from personal experience).

This follows (parts of) advice in `perldoc -f do` documentation.

This required restructoring code a bit, so we die only if we are reading
(executing) config file.  As a side effect $GITWEB_CONFIG_SYSTEM is always
available, even when we use $GITWEB_CONFIG.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -550,11 +550,14 @@ sub filter_snapshot_fmts {
 }
 
 our $GITWEB_CONFIG = $ENV{'GITWEB_CONFIG'} || "++GITWEB_CONFIG++";
+our $GITWEB_CONFIG_SYSTEM = $ENV{'GITWEB_CONFIG_SYSTEM'} || "++GITWEB_CONFIG_SYSTEM++";
+# die if there are errors parsing config file
 if (-e $GITWEB_CONFIG) {
 	do $GITWEB_CONFIG;
-} else {
-	our $GITWEB_CONFIG_SYSTEM = $ENV{'GITWEB_CONFIG_SYSTEM'} || "++GITWEB_CONFIG_SYSTEM++";
-	do $GITWEB_CONFIG_SYSTEM if -e $GITWEB_CONFIG_SYSTEM;
+	die $@ if $@;
+} elsif (-e $GITWEB_CONFIG_SYSTEM) {
+	do $GITWEB_CONFIG_SYSTEM;
+	die $@ if $@;
 }
 
 # Get loadavg of system, to compare against $maxload.