put back 'choices' that were accidentally dropped from goodness.cca

choices were unintentionally dropped when goodness.cca was replaced
with the new code (then goodness2.cca) in a231931. They are still
documented but won't work.

There are many ways of doing this as discussed in issue #190 in github

(cherry picked from commit 4026ba4)

R/goodness.cca.R

@@ -20,6 +20,12 @@
     ## imaginary dimensions for dbrda
     if (inherits(object, "dbrda"))
         CA <- cbind(CA, object[[model]][["imaginary.u"]])
+    ## take only chosen axes within the component
+    if (!missing(choices)) {
+        choices <- choices[choices <= ncol(CA)]
+        CA <- CA[, choices, drop = FALSE]
+        eig <- eig[choices]
+    }
     att <- attributes(CA)
     if (inherits(object, "rda"))
         nr <- nobs(object) - 1