Add TWFunc::Exec_Cmd() with no 'result' agrument

Signed-off-by: Vojtech Bocek <vbocek@gmail.com>

Change-Id: Id8acff1ac9b3c7e4b562c80562a8ff42a1d132b9
diff --git a/twrp.cpp b/twrp.cpp
index 57e1657..765cad3 100644
--- a/twrp.cpp
+++ b/twrp.cpp
@@ -187,13 +187,12 @@
 #ifdef TW_INCLUDE_INJECTTWRP
 	// Back up TWRP Ramdisk if needed:
 	TWPartition* Boot = PartitionManager.Find_Partition_By_Path("/boot");
-	string result;
 	LOGINFO("Backing up TWRP ramdisk...\n");
 	if (Boot == NULL || Boot->Current_File_System != "emmc")
-		TWFunc::Exec_Cmd("injecttwrp --backup /tmp/backup_recovery_ramdisk.img", result);
+		TWFunc::Exec_Cmd("injecttwrp --backup /tmp/backup_recovery_ramdisk.img");
 	else {
 		string injectcmd = "injecttwrp --backup /tmp/backup_recovery_ramdisk.img bd=" + Boot->Actual_Block_Device;
-		TWFunc::Exec_Cmd(injectcmd, result);
+		TWFunc::Exec_Cmd(injectcmd);
 	}
 	LOGINFO("Backup of TWRP ramdisk done.\n");
 #endif