sh256: remove training wheels

kiss

@@ -141,19 +141,16 @@ sh256() {
     # All utilities must match 'sha256sum' output.
     #
     # Example: '<checksum>  <file>'
-
-    if [ ! -d "$1" ] && [ -e "$1" ]; then
     hash=$(
         sha256sum               "$1" ||
         sha256 -r               "$1" ||
         openssl dgst -sha256 -r "$1" ||
         shasum -a 256           "$1" ||
         digest -a sha256        "$1"
-        ) 2>/dev/null
+    ) 2>/dev/null || die "Failed to generate checksums for '$1'"
 
     hash=${hash%% *}
     printf '%s\n' "$hash"
-    fi
 }
 
 pkg_lint() {