build-and-provide-package: rework package removal for arch-all packages

We can't remove a package from the repository in the step where
we're checking for missing binary packages (to get rid of packages
which are no longer provided but shouldn't stay in the archive)
if the package is an 'Architecture: all' one, as e.g. the i386
build might remove the package from the amd64 build.

So let's check for "-B" in DEBBUILDOPTS and then skip the removal
process in such a situation...

scripts/build-and-provide-package

@@ -278,7 +278,7 @@ remove_packages() {
 
     # note: "removesrc" would remove foreign arch files (of different builds)
     if echo "$file" | egrep -q '_all.deb$'; then
-      echo "*** Removing existing package ${binpackage} from repository ${REPOS} ***"
+      echo "*** Removing existing package ${binpackage} from repository ${REPOS} (arch all) ***"
       ${SUDO_CMD:-} reprepro -v -b "${REPOSITORY}" --waitforlock 1000 remove "${REPOS}" "${binpackage}"
     else
       echo "*** Removing existing package ${binpackage} from repository ${REPOS} for arch ${ARCH} ***"
@@ -290,12 +290,27 @@ remove_packages() {
 }
 
 remove_missing_binary_packages() {
-  for p in $(${SUDO_CMD:-} reprepro -v -b "${REPOSITORY}" --waitforlock 1000 listmatched "${REPOS}" '*' | awk '{print $2}' | sort -u); do
+  echo "*** Checking for missing binary packages to be considered for removal ***"
+
+  # In a binary-only build we don't get any arch-all (*_all.deb) packages and
+  # therefore they won't be listed in the changes file.  As a result they would
+  # be reported as missing from the build and to be considered for removal.
+  # As we don't want to remove the arch-all package e.g. from the amd64 repos
+  # in the i386 run we've to skip the removal procedure then.
+  case "$DEBBUILDOPTS" in
+    *-B*)
+      echo "*** Skipping removal of missing binaries as being a binary-only build ***"
+      return 0
+      ;;
+  esac
+
+  for p in $(${SUDO_CMD:-} reprepro -v -b "${REPOSITORY}" --waitforlock 1000 --list-format '${package}\n' listmatched "${REPOS}" '*' | sort -u); do
     echo "$binary_list" | grep -q "$p" || missing_packages="${missing_packages:-} $p"
   done
 
-  if echo "${missing_packages:-}" | grep -q '[a-z0-9]' ; then
+  if echo "${missing_packages:-}" | grep -q '.' ; then
     echo "*** Binary package(s) found, missing in build version: ${missing_packages:-} ***"
+
     for p in $missing_packages ; do
       echo "*** Removing $p from $REPOS to avoid out-of-date data ***"
       ${SUDO_CMD:-} reprepro -v -b "${REPOSITORY}" --waitforlock 1000 remove "${REPOS}" "${p}"