[autotools,bugfix] Remove existent file when installing CMake's package version configuration.

The temporary file <dune-module>-config-version.tmp!
(cherry picked from commit 9775442a)

Signed-off-by: Markus Blatt <markus@dr-blatt.de>

am/cmake-pkg-config

@@ -38,6 +38,6 @@ install-exec-local:
         echo "  endif()" >> $(PACKAGE)-config-version.tmp; \
    	echo "endif()" >> $(PACKAGE)-config-version.tmp; \
 	$(INSTALL_DATA) $(PACKAGE)-config-version.tmp $(DESTDIR)$(libdir)/cmake/$(PACKAGE)/$(PACKAGE)-config-version.cmake; \
-        rm $(PACKAGE)-config-version.cmake
+        rm $(PACKAGE)-config-version.tmp