conf / scripts: Fix unprivileged "make install"

Unprivileged "make install" currently returns an error. That looks bad.

It actually is not a real problem, because unprivileged "make install"
installs files into locations that are good for nothing, in the sense
that they don't constitute a meaningful or usable hierarchy of installed
files. Debugging / inspecting the install machinery itself is a valid
use case, though, and it's easier to explain to the unsuspecting user
that unprivileged installation is something akin to shooting range
training than why "make install" outright errors out, so fix the error
messages.

Signed-off-by: Jan Lindemann <jan@janware.com>

conf/bash-completion.d/Makefile

@@ -1,6 +1,6 @@
 TOPDIR                       = ../..
 
-INSTALL_CFGDIR = $(ENV_PREFIX)/usr/share/bash-completion/completions
+INSTALL_CFGDIR               = $(ROOT_PREFIX)/usr/share/bash-completion/completions
 LOCAL_CFG                    = $(filter-out Makefile,$(wildcard *))
 PACKAGE_INSTALL_DIR          = false
 

scripts/usr-bin/Makefile

@@ -1,6 +1,6 @@
 TOPDIR = ../..
 
-TARGET_DIR = $(ENV_PREFIX)/usr/bin
+TARGET_DIR = $(ROOT_PREFIX)/usr/bin
 
 include $(TOPDIR)/make/proj.mk
 include $(JWBDIR)/make/defs.mk