Fix `go vet` issues

Test: go vet ./...
Change-Id: Ifb936ccc5e2b5a2c3fcbbbcb54f680e2973ea1b3
diff --git a/ui/build/environment.go b/ui/build/environment.go
index 8589937..cbeeb4b 100644
--- a/ui/build/environment.go
+++ b/ui/build/environment.go
@@ -134,7 +134,7 @@
 		if cmd[0] == "unset" {
 			str, ok := singleUnquote(cmd[1])
 			if !ok {
-				fmt.Errorf("Failed to unquote kati line: %q", text)
+				return fmt.Errorf("Failed to unquote kati line: %q", text)
 			}
 			e.Unset(str)
 		} else if cmd[0] == "export" {
diff --git a/ui/status/ninja.go b/ui/status/ninja.go
index 7d330f9..4ceb5ef 100644
--- a/ui/status/ninja.go
+++ b/ui/status/ninja.go
@@ -43,7 +43,7 @@
 func ninjaReader(status ToolStatus, fifo string) {
 	f, err := os.Open(fifo)
 	if err != nil {
-		status.Error(fmt.Sprintf("Failed to open fifo:", err))
+		status.Error(fmt.Sprintf("Failed to open fifo: %v", err))
 	}
 	defer f.Close()