test/chan/select5.go: change "with" to "if" in templatea

I converted this program yesterday and the output is the
same as it used to be, ignoring space, but the result is
not the best expression of the algorithm.  The old {.section
Maybe} pieces are now {{with .Maybe}}, as a direct translation,
but I they should be {{if .Maybe}} as the output is just a
bool and there is no cascading.

I have verified that the output of the program is unaffected.

R=golang-dev, dsymonds
1 file changed