fix bug

tasks/MD5.wdl

@@ -6,7 +6,7 @@ task MD5 {
 	String disk_size
 
 	command <<<
-		md5sum ${file} > $(basename ${file}).md5
+		md5sum ${file} > $(basename ${file}.md5)
 	>>>
 
 	runtime {
@@ -17,6 +17,6 @@ task MD5 {
 	}
 
 	output {
-		File MD5 = "$(basename ${file}).md5"
+		File MD5 = "$(basename ${file}.md5)"
 	}
 }