Revert "broker: Allow colons in journal names and label values"

This reverts commit f28f519.

The downstream requirement has gone away, and there's no current known
reason to expand the set of allowed tokens.

broker/protocol/journal_spec_extensions_test.go

@@ -16,7 +16,6 @@ func (s *JournalSuite) TestJournalValidationCases(c *gc.C) {
 		expect string
 	}{
 		{"a/valid/path/to/a/journal", ""}, // Success.
-		{"a/valid/path/to/a:journal", ""}, // Success.
 		{"/leading/slash", `cannot begin with '/' \(/leading/slash\)`},
 		{"trailing/slash/", `must be a clean path \(trailing/slash/\)`},
 		{"extra-middle//slash", `must be a clean path \(extra-middle//slash\)`},

broker/protocol/label_extensions_test.go

@@ -16,10 +16,8 @@ func (s *LabelSuite) TestLabelValidationCases(c *gc.C) {
 	}{
 		{"a-label", "a-value", ""},   // Success.
 		{"a/label", "a%20value", ""}, // Success.
-		{"a-label", "a:value", ""},   // Success
 		{"a|label", "a-value", `Name: not a valid token \(a|label\)`},
 		{"a-label", "a|value", `Value: not a valid token \(a|value\)`},
-		{"a:label", "a-value", `Name: not a valid token \(a:label\)`},
 		{"a", "a-value", `Name: invalid length \(1; expected 2 <= length <= 64\)`},
 		{strings.Repeat("a", maxLabelLen+1), "a-value", `Name: invalid length \(65; expected .*`},
 		{"a-label", "", ""}, // Success

broker/protocol/validator.go

@@ -86,6 +86,6 @@ const (
 	// The alphabet leads with '-' to facilitate escaping in |reToken|.
 	TokenSymbols = "-_+/."
 	// pathSymbols is allowed runes of strings which form path components.
-	// It extends TokenSymbols with the '=', '%', and ':' runes.
-	pathSymbols = TokenSymbols + "=%:"
+	// It extends TokenSymbols with the '=' and '%' runes.
+	pathSymbols = TokenSymbols + "=%"
 )