Dpkg::Control::FieldsCore: Allow the Maintainer field in CTRL_FILE_STATUS

This field is part of the status field.

debian/changelog

@@ -16,6 +16,7 @@ dpkg (1.18.2) UNRELEASED; urgency=low
     - Remove trailing space before handling blank line dot-separator in
       Dpkg::Control::HashCore. Regression introduced in dpkg 1.18.0.
       Reported by Jakub Wilk <jwilk@debian.org>. Closes: #789580
+    - Allow the Maintainer field in CTRL_FILE_STATUS.
   * Documentation:
     - Fix grammar in dpkg-architecture(1).
       Thanks to Chris Lamb <lamby@debian.org>. Closes: #787616

scripts/Dpkg/Control/FieldsCore.pm

@@ -213,7 +213,7 @@ our %FIELDS = (
         allowed => (ALL_PKG | ALL_SRC) & (~CTRL_INFO_PKG),
     },
     'Maintainer' => {
-        allowed => CTRL_PKG_DEB | ALL_SRC | ALL_CHANGES,
+        allowed => CTRL_PKG_DEB| CTRL_FILE_STATUS | ALL_SRC  | ALL_CHANGES,
     },
     'Multi-Arch' => {
         allowed => ALL_PKG,