Do not replace the T delimiter with a space to respect the ISO 8601 norm

From Wikipedia:
"""
A single point in time can be represented by concatenating a complete date
expression, the letter "T" as a delimiter, and a valid time expression.
For example, "2007-04-05T14:30".
Separating date and time parts with other characters such as space is not
allowed in ISO 8601, but allowed in its profile RFC 3339.
"""

The "T" delimiter is now correctly supported by GNAT.Calendar.Time_IO.

Author: Jicquel

src/gnatcoll-utils.adb

@@ -757,21 +757,10 @@ package body GNATCOLL.Utils is
          end if;
       end loop;
 
-      --  In ISO format, the separator between date and time is 'T', whereas
-      --  GNAT.Calendar.Time_IO expects as space.
-
       declare
-         S2    : String := Str (First .. Last);
-         Local : Ada.Calendar.Time;
+         Local : constant Ada.Calendar.Time :=
+                   GNAT.Calendar.Time_IO.Value (Str (First .. Last));
       begin
-         for S in S2'Range loop
-            if S2 (S) = 'T' then
-               S2 (S) := ' ';
-               exit;
-            end if;
-         end loop;
-
-         Local := GNAT.Calendar.Time_IO.Value (S2);
 
          --  GNAT.Calendar.Time_IO.Value uses Ada.Calendars.Time_Of, which
          --  for GNAT assumes the input date is in the local time zone.