persist logs: remove persist from available log directories in
partitions.

Too many problems have been reported for TWRP attempting to store
logs in the persist partition. Selinux denials have caused issues
booting Android, and filling up persist has caused IMEI issues.

This patchset will remove persist from the list of available log
directories by default in order to avoid these and other possible
issues.

Change-Id: I9f5347875a6cab24ab83ad48476b17a174e65c43
diff --git a/twrp-functions.cpp b/twrp-functions.cpp
index ae1d133..2ac4c95 100755
--- a/twrp-functions.cpp
+++ b/twrp-functions.cpp
@@ -761,7 +761,7 @@
 	PartitionManager.Mount_By_Path(src, false);
 	PartitionManager.Mount_By_Path(dst, false);
 	if (!Path_Exists(src)) {
-		LOGINFO("Unable to find source file %s\n", src.c_str());
+		LOGINFO("Path %s does not exist. Unable to copy %s\n", src.c_str(), dst.c_str());
 		return -1;
 	}
 	std::ifstream srcfile(src.c_str(), ios::binary);
@@ -1250,11 +1250,8 @@
 std::string TWFunc::get_log_dir() {
 	if (PartitionManager.Find_Partition_By_Path(CACHE_LOGS_DIR) == NULL) {
 		if (PartitionManager.Find_Partition_By_Path(DATA_LOGS_DIR) == NULL) {
-			if (PartitionManager.Find_Partition_By_Path(PERSIST_LOGS_DIR) == NULL) {
-				LOGINFO("Unable to find a directory to store TWRP logs.");
-				return "";
-			}
-			return PERSIST_LOGS_DIR;
+			LOGINFO("Unable to find a directory to store TWRP logs.");
+			return "";
 		} else {
 			return DATA_LOGS_DIR;
 		}