Address run/create performance issues

Fixed the logic where we observed different performance
results when running an image by its fqname vs a shortname. In
the case of the latter, we resolve the name without using the
network.

Signed-off-by: baude <bbaude@redhat.com>

Closes: #37
Approved by: rhatdan

libpod/util.go

@@ -1,8 +1,10 @@
 package libpod
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
+	"time"
 )
 
 // WriteFile writes a provided string to a provided path
@@ -32,3 +34,11 @@ func StringInSlice(s string, sl []string) bool {
 	}
 	return false
 }
+
+// FuncTimer helps measure the execution time of a function
+// For debug purposes, do not leave in code
+// used like defer FuncTimer("foo")
+func FuncTimer(funcName string) {
+	elapsed := time.Since(time.Now())
+	fmt.Printf("%s executed in %d ms\n", funcName, elapsed)
+}