Trim baggage key when parsing (#566)

Signed-off-by: lastchiliarch <lastchiliarch@gmail.com>

propagation.go

@@ -292,7 +292,7 @@ func (p *TextMapPropagator) parseCommaSeparatedMap(value string) map[string]stri
 	for _, kvpair := range strings.Split(value, ",") {
 		kv := strings.Split(strings.TrimSpace(kvpair), "=")
 		if len(kv) == 2 {
-			baggage[kv[0]] = kv[1]
+			baggage[strings.TrimSpace(kv[0])] = kv[1]
 		} else {
 			log.Printf("Malformed value passed in for %s", p.headerKeys.JaegerBaggageHeader)
 		}

propagation_test.go

@@ -257,6 +257,7 @@ func TestParseCommaSeperatedMap(t *testing.T) {
 		{"malformed", map[string]string{}},
 		{"malformed, string", map[string]string{}},
 		{"another malformed string", map[string]string{}},
+		{"key2=value2,    key3    =    value3   ", map[string]string{"key2": "value2", "key3": "    value3"}},
 	}
 
 	for _, testcase := range testcases {