examples/version/check_in_make breaks "make clean" if version file not present

``` make[3]: Entering directory '/home/asie/wonderful/blocksds/examples/version/check_in_make' Makefile:18: *** BlocksDS version too old. Please update.. Stop. make[3]: Leaving directory '/home/asie/wonderful/blocksds/examples/version/check_in_make' ```