check return values of fread

check return values of fread

Fixes:
utilities/hogcreate.c:66:11: error: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Werror=unused-result]
utilities/hogextract.c:47:7: error: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Werror=unused-result]
utilities/hogextract.c:51:8: error: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Werror=unused-result]
utilities/hogextract.c:52:8: error: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Werror=unused-result]
utilities/hogextract.c:67:11: error: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Werror=unused-result]
utilities/mvlcreate.c:87:9: error: ignoring return value of ‘fread’, declared with attribute warn_unused_result [-Werror=unused-result]