text/template: handle panic values that are not errors.
text/template: handle panic values that are not errors.

The recover code assumes that the panic() argument was
an error, but it is usually a simple string.
Fixes issue 2663.

R=golang-dev, r, r, gri
CC=golang-dev, remy
http://codereview.appspot.com/5527046

Committer: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,gnanderson/go,tv42/old-go,apparentlymart/golang,apparentlymart/golang,dsriram/golang,apparentlymart/golang,pombredanne/go-deleteme,gnanderson/go,apparentlymart/golang,apparentlymart/golang,pombredanne/go-deleteme,dsriram/golang,dsriram/golang,apparentlymart/golang,apparentlymart/golang,pombredanne/go-deleteme,dsriram/golang,tv42/old-go,dsriram/golang,tv42/old-go,tv42/old-go,gnanderson/go,pombredanne/go-deleteme,tv42/old-go,pombredanne/go-deleteme,gnanderson/go,gnanderson/go,gnanderson/go,dsriram/golang,tv42/old-go