Finish vitastor-disk prepare in theory

src/str_util.h

@@ -9,7 +9,7 @@ std::string base64_encode(const std::string &in);
 std::string base64_decode(const std::string &in);
 uint64_t parse_size(std::string size_str);
 std::string strtolower(const std::string & in);
-std::string trim(const std::string & in);
+std::string trim(const std::string & in, const char *rm_chars = " \n\r\t");
 std::string str_replace(const std::string & in, const std::string & needle, const std::string & replacement);
 uint64_t stoull_full(const std::string & str, int base = 0);
 std::string format_size(uint64_t size, bool nobytes = false);