style(cmd/ipfs/pprof) move defer close to initialization

cmd/ipfs/Makefile

@@ -5,3 +5,11 @@ build:
 
 install: build
 	go install
+
+# cpu profiling: `go tool pprof ipfs cpu.prof`
+# mem profiling: `go tool pprof ipfs ipfs.mprof`
+
+clean:
+	rm -f cpu.prof
+	rm -f ipfs.mprof
+	rm -f ipfs

cmd/ipfs/ipfs.go

@@ -99,12 +99,14 @@ func main() {
 	// if debugging, setup profiling.
 	if u.Debug {
 		ofi, err := os.Create("cpu.prof")
+		defer ofi.Close()
+
 		if err != nil {
 			fmt.Println(err)
 			return
 		}
+
 		pprof.StartCPUProfile(ofi)
-		defer ofi.Close()
 		defer pprof.StopCPUProfile()
 	}