Makefile.install: rm trailing slash from instdirs

These variables doesn't need to end with a slash.
This helps the next patch.

travis-ci: success for More polishing for compel cli
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Makefile.install

@@ -4,10 +4,10 @@ PREFIX		?= /usr/local
 BINDIR		?= $(PREFIX)/bin
 SBINDIR		?= $(PREFIX)/sbin
 MANDIR		?= $(PREFIX)/share/man
-SYSTEMDUNITDIR	?= $(PREFIX)/lib/systemd/system/
-LOGROTATEDIR	?= $(PREFIX)/etc/logrotate.d/
+SYSTEMDUNITDIR	?= $(PREFIX)/lib/systemd/system
+LOGROTATEDIR	?= $(PREFIX)/etc/logrotate.d
 LIBDIR		?= $(PREFIX)/lib
-INCLUDEDIR	?= $(PREFIX)/include/
+INCLUDEDIR	?= $(PREFIX)/include
 LIBEXECDIR	?= $(PREFIX)/libexec
 
 #