[Dovecot] Another 2.0.alpha2 panic

[Mike Abbott]

This time using maildir instead of mdbox.

Fri Oct 30 21:08:16 server dovecot[27407]: lda(pid 27407 user userW):  
Panic: file istream.c: line 104 (i_stream_read): assertion failed:  
((size_t)ret+old_size == _stream->pos - _stream->skip)
0   libSystem.B.dylib             	0x00007fff875f4eba __kill + 10
1   libSystem.B.dylib             	0x00007fff875f4eac kill + 14
2   libSystem.B.dylib             	0x00007fff87683519 raise + 25
3   libSystem.B.dylib             	0x00007fff876a4e12 abort + 90
4   libdovecot.0.dylib            	0x00000001000d1027  
i_set_failure_file + 275
5   libdovecot.0.dylib            	0x00000001000d03ec  
i_syslog_error_handler + 0
6   libdovecot.0.dylib            	0x00000001000d06d2 i_debug + 0
7   libdovecot.0.dylib            	0x00000001000d9c00 i_stream_read +  
392
8   libdovecot.0.dylib            	0x00000001000d8104  
i_stream_create_limit + 436
9   libdovecot.0.dylib            	0x00000001000d9ab7 i_stream_read + 63
10  libdovecot.0.dylib            	0x00000001000d9cf1  
i_stream_read_data + 103
11  libdovecot.0.dylib            	0x00000001000c4bef  
message_parse_header_next + 145
12  libdovecot.0.dylib            	0x00000001000c646f  
message_parser_init_from_parts + 287
13  libdovecot.0.dylib            	0x00000001000c5a4b  
message_parser_parse_next_block + 133
14  libdovecot.0.dylib            	0x00000001000c5bc8  
message_parser_parse_header + 64
15  libdovecot-storage.0.dylib    	0x0000000100043883  
index_mail_parse_headers + 189
16  libdovecot-storage.0.dylib    	0x0000000100043b53  
index_mail_get_header_stream + 597
17  libdovecot-storage.0.dylib    	0x0000000100043f89  
index_mail_get_first_header + 49
18  libdovecot-storage.0.dylib    	0x0000000100011d1d  
mail_get_first_header + 15
19  dovecot-lda                   	0x0000000100002eda  
mail_deliver_get_address + 24
20  dovecot-lda                   	0x00000001000020f0 main + 2484
21  dovecot-lda                   	0x0000000100001734 start + 52