permit leading whitespace in INTERNALDATE strings

the BNF specifies "(SP DIGIT) / 2DIGIT" for the date-day-fixed symbol,
but "*SP 1*DIGIT" matches that closely enough for parsing purposes.

REFMAIL: CYYDEEVZ8CCT.2M1T7XKT45HH8@jonas.vautherin.ch

src/drv_imap.c

@@ -1031,7 +1031,7 @@ parse_date( const char *str )
 	struct tm datetime;
 
 	memset( &datetime, 0, sizeof(datetime) );
-	if (!(end = strptime( str, "%e-%b-%Y %H:%M:%S ", &datetime )))
+	if (!(end = strptime( str, " %e-%b-%Y %H:%M:%S ", &datetime )))
 		return -1;
 	if ((date = timegm( &datetime )) == -1)
 		return -1;