fix syntax error in logrotate file

From logrotate(8):

Values are separated from directives by whitespace and/or an
optional =. Numbers must be specified in a format understood by
strtoul(3).

Since logrotate 3.18.1 emits a warning if the keyword is not properly separated from the value 1. This causes error messages such as:

rsyncd:5 keyword 'size' not properly separated, found 0x3d

During log rotate. This commit fixes the sync error in the logrotate script for rsyncd.