libgo: avoid use of 'local' directive in shell script

Avoid declaring shell variables with 'local' (not supported
on all systems of interest).

Change-Id: I2ba17ae5fca29034b6de73e093dfcbe1537ff770
Reviewed-on: https://go-review.googlesource.com/c/145021
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed