Fix bug when sfpi__key() would not ever return anything

src/include-bash/sfpi.sh

@@ -226,14 +226,17 @@ sfpi__key() {
     local key=$2    # meta-data key
     local value     # ^^ value
     local fun="${SFPI__PREFIX}_${plg}__sfpimeta" # plg getter function name
-    if type -t "$fun" >/dev/null; then
-        value=$("$fun" "$key")
-        debug -v fun key value
-        test -n "$value" || value="(none)"
-    else
-        value='(undefined)'
-    fi
-    echo "$value"
+    (
+        sfpi__import "$plg"
+        if type -t "$fun" >/dev/null; then
+            value=$("$fun" "$key")
+            debug -v fun key value
+            test -n "$value" || value="(none)"
+        else
+            value='(undefined)'
+        fi
+        echo "$value"
+    )
 }
 
 sfpi__ls_all() {