Provide installation target without documentation

The criu(8) man-page is generated using asciidoc. The problem with
asciidoc is that, due to its dependencies, it is not available on
all distributions or it is undesired to install all asciidoc
dependencies. The install target was unconditionally installing and thus
building the man-page even if not explicitly specified with 'make docs'.
With the new 'install-criu' target everything besides the man-page is
installed and the target 'install-man' is only called by the target
'install'.
Signed-off-by: Adrian Reber <areber@redhat.com>
Acked-by: Tycho Andersen <tycho.andersen@canonical.com>
Looks-ok-to: Cyril Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

Makefile

@@ -284,7 +284,9 @@ criu-$(CRTOOLSVERSION).tar.bz2:
 		v$(CRTOOLSVERSION) | bzip2 > $@
 .PHONY: dist tar
 
-install: $(PROGRAM) $(CRIU-LIB) install-man install-crit
+install: install-criu install-man 
+
+install-criu: $(PROGRAM) $(CRIU-LIB) install-crit
 	$(E) "  INSTALL " $(PROGRAM)
 	$(Q) mkdir -p $(DESTDIR)$(SBINDIR)
 	$(Q) install -m 755 $(PROGRAM) $(DESTDIR)$(SBINDIR)
@@ -316,7 +318,7 @@ install-crit: crit
 	$(E) "  INSTALL crit"
 	$(Q) python scripts/crit-setup.py install --root=$(DESTDIR) --prefix=$(PREFIX)
 
-.PHONY: install install-man install-crit
+.PHONY: install install-man install-crit install-criu
 
 help:
 	@echo '    Targets:'