packaging: move dockerrpm output directory creation to dockerrpm

Avoid having to compute the directory in two places in different environments.

contrib/packaging/Makefile

@@ -105,7 +105,6 b' fedora$(1):'
 
 .PHONY: docker-fedora$(1)
 docker-fedora$(1):
-	mkdir -p $$(HGROOT)/packages/fedora$(1)
 	./dockerrpm fedora$(1)
 
 endef
@@ -123,7 +122,6 b' centos$(1):'
 
 .PHONY: docker-centos$(1)
 docker-centos$(1):
-	mkdir -p $$(HGROOT)/packages/centos$(1)
 	./dockerrpm centos$(1) $$(if $$(filter $(1),$$(CENTOS_WITH_PYTHON_RELEASES)),--withpython)
 
 endef

contrib/packaging/dockerrpm

@@ -21,6 +21,7 b' fi'
 $BUILDDIR/hg-docker build --build-arg UID=$DOCKERUID --build-arg GID=$DOCKERGID $BUILDDIR/docker/$PLATFORM $CONTAINER
 
 RPMBUILDDIR=$ROOTDIR/packages/$PLATFORM
+mkdir -p $RPMBUILDDIR
 $ROOTDIR/contrib/packaging/buildrpm --rpmbuilddir $RPMBUILDDIR --prepare $*
 
 DSHARED=/mnt/shared