incorrect syntax DNS

Line 68: email does not arobase,replaced by a point
Line 69: Serial recommended format (per RFC1912 2.2) is YYYYMMDDnn and "ID" (YYYYMMDDnnID)
incorrect syntax DNS

Line 1635: email does not arobase,replaced by a point
Line 1636: Serial recommended format (per RFC1912 2.2) is YYYYMMDDnn and "ID" (YYYYMMDDnnID)
Merge pull request #19 from ZPanelFR/master

Correction of DNS syntax for postmaster setting.
Merge request from ZPanelFR.