Add "-f" to GNUPGHOME deletions (helps avoid a GnuPG 2.x race condition)

This is the race condition that has been plaguing the official build for the past many hours, and we've found that adding "-f" helps mitigate it (doesn't completely eliminate it, but it's a dramatic improvement in the successful build ratio).

mainline/alpine-perl/Dockerfile

@@ -82,7 +82,7 @@ RUN GPG_KEYS=B0F4253373F8F6F510D42178520A9993A1C052F8 \
 	done; \
 	test -z "$found" && echo >&2 "error: failed to fetch GPG key $GPG_KEYS" && exit 1; \
 	gpg --batch --verify nginx.tar.gz.asc nginx.tar.gz \
-	&& rm -r "$GNUPGHOME" nginx.tar.gz.asc \
+	&& rm -rf "$GNUPGHOME" nginx.tar.gz.asc \
 	&& mkdir -p /usr/src \
 	&& tar -zxC /usr/src -f nginx.tar.gz \
 	&& rm nginx.tar.gz \

mainline/alpine/Dockerfile

@@ -80,7 +80,7 @@ RUN GPG_KEYS=B0F4253373F8F6F510D42178520A9993A1C052F8 \
 	done; \
 	test -z "$found" && echo >&2 "error: failed to fetch GPG key $GPG_KEYS" && exit 1; \
 	gpg --batch --verify nginx.tar.gz.asc nginx.tar.gz \
-	&& rm -r "$GNUPGHOME" nginx.tar.gz.asc \
+	&& rm -rf "$GNUPGHOME" nginx.tar.gz.asc \
 	&& mkdir -p /usr/src \
 	&& tar -zxC /usr/src -f nginx.tar.gz \
 	&& rm nginx.tar.gz \

stable/alpine-perl/Dockerfile

@@ -82,7 +82,7 @@ RUN GPG_KEYS=B0F4253373F8F6F510D42178520A9993A1C052F8 \
 	done; \
 	test -z "$found" && echo >&2 "error: failed to fetch GPG key $GPG_KEYS" && exit 1; \
 	gpg --batch --verify nginx.tar.gz.asc nginx.tar.gz \
-	&& rm -r "$GNUPGHOME" nginx.tar.gz.asc \
+	&& rm -rf "$GNUPGHOME" nginx.tar.gz.asc \
 	&& mkdir -p /usr/src \
 	&& tar -zxC /usr/src -f nginx.tar.gz \
 	&& rm nginx.tar.gz \

stable/alpine/Dockerfile

@@ -80,7 +80,7 @@ RUN GPG_KEYS=B0F4253373F8F6F510D42178520A9993A1C052F8 \
 	done; \
 	test -z "$found" && echo >&2 "error: failed to fetch GPG key $GPG_KEYS" && exit 1; \
 	gpg --batch --verify nginx.tar.gz.asc nginx.tar.gz \
-	&& rm -r "$GNUPGHOME" nginx.tar.gz.asc \
+	&& rm -rf "$GNUPGHOME" nginx.tar.gz.asc \
 	&& mkdir -p /usr/src \
 	&& tar -zxC /usr/src -f nginx.tar.gz \
 	&& rm nginx.tar.gz \