panic can't print interfaces well so use err.String()

R=rsc
http://go/go-review/1016041

src/pkg/regexp/regexp.go

@@ -630,7 +630,7 @@ func Compile(str string) (regexp *Regexp, error os.Error) {
 func MustCompile(str string) *Regexp {
 	regexp, error := Compile(str);
 	if error != nil {
-		panicln(`regexp: compiling "`, str, `": `, error);
+		panicln(`regexp: compiling "`, str, `": `, error.String());
 	}
 	return regexp;
 }

src/pkg/template/template.go

@@ -898,7 +898,7 @@ func Parse(s string, fmap FormatterMap) (t *Template, err os.Error) {
 func MustParse(s string, fmap FormatterMap) *Template {
 	t , err := Parse(s, fmap);
 	if err != nil {
-		panic("template parse error: ", err);
+		panic("template parse error: ", err.String());
 	}
 	return t
 }