download: make it pass shellcheck

Without that fix, running 'shellcheck -x build' produces the following
errors/warnings:
    In download line 26:
    [ "x${DEBUG+set}" = 'xset' ] && set -v
      ^-------------^ SC2268 (style):
    Avoid x-prefix in comparisons as it no longer serves a purpose.

    In download line 37:
    [ "x${NODELETE+set}" = 'xset' ] && deleteblobs="false"
      ^----------------^ SC2268 (style):
    Avoid x-prefix in comparisons as it no longer serves a purpose.

    In download line 102:
    NODELETE= "${script}"
             ^-- SC1007 (warning):
    Remove space after = if trying to assign a value (for empty string,
    use var='' ... ).

    In download line 117:
    NODELETE= resources/packages/"${package}"/download
             ^-- SC1007 (warning):
    Remove space after = if trying to assign a value (for empty string,
    use var='' ... ).

    In download line 123:
    NODELETE= resources/packages/"${package}"/download $@
             ^-- SC1007 (warning):
    Remove space after = if trying to assign a value (for empty string,
    use var='' ... ).
                                                       ^-- SC2068 (error):
    Double quote array expansions to avoid re-splitting elements.

    In download line 125:
    resources/packages/"${package}"/download $@
                                             ^-- SC2068 (error):
    Double quote array expansions to avoid re-splitting elements.

    In download line 131:
    ./.gitcheck clean
    ^---------------^ SC2317 (info):
    Command appears to be unreachable. Check usage (or ignore if invoked
    indirectly).

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
Acked-by: Adrien 'neox' Bourmault <neox@gnu.org>

download

@@ -21,9 +21,10 @@
 #	along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+# shellcheck source=.gitcheck
 ./.gitcheck
 
-[ "x${DEBUG+set}" = 'xset' ] && set -v
+[ "${DEBUG+set}" = 'set' ] && set -v
 set -u -e
 
 ./resources/scripts/misc/versioncheck
@@ -32,9 +33,9 @@ set -u -e
 
 # set this when you want to modify each coreboot tree
 # for example, you want to test custom patches
-# NODELETE= ./download coreboot
+# NODELETE='' ./download coreboot
 deleteblobs="true"
-[ "x${NODELETE+set}" = 'xset' ] && deleteblobs="false"
+[ "${NODELETE+set}" = 'set' ] && deleteblobs="false"
 
 rm -f "build_error"
 
@@ -99,7 +100,7 @@ shift 1
 if [ "${package}" = "all" ]; then
 	for script in resources/packages/*/download; do
 		if [ "${deleteblobs}" = "false" ]; then
-			NODELETE= "${script}"
+			NODELETE='' "${script}"
 		else
 			"${script}"
 		fi
@@ -114,18 +115,21 @@ fi
 
 if [ $# -lt 1 ]; then
 	if [ "${deleteblobs}" = "false" ]; then
-		NODELETE= resources/packages/"${package}"/download
+		NODELETE='' resources/packages/"${package}"/download
 	else
 		resources/packages/"${package}"/download
 	fi
 else
 	if [ "${deleteblobs}" = "false" ]; then
-		NODELETE= resources/packages/"${package}"/download $@
+		# shellcheck disable=SC2068
+		NODELETE='' resources/packages/"${package}"/download $@
 	else
+		# shellcheck disable=SC2068
 		resources/packages/"${package}"/download $@
 	fi
 fi
 
-exit 0
-
+# shellcheck disable=SC2317
 ./.gitcheck clean
+
+exit 0

tests/lint

@@ -42,6 +42,7 @@ printf "| Running lint tests: |\n"
 printf "+---------------------+\n"
 run_shellcheck \
     build \
+    download \
     modify \
     resources/packages/descriptors/distclean \
     resources/packages/flashrom/distclean \