Use access = "stream" by default

Author: certik

Diff for: src/stdlib_experimental_io.f90

@@ -335,15 +335,15 @@ integer function open(filename, mode, iostat) result(u)
 
 select case (mode_(3:3))
 case('t')
-    access_='sequential'
     form_='formatted'
 case('b', 's')
-    access_='stream'
     form_='unformatted'
 case default
     call error_stop("Unsupported mode: "//mode_(3:3))
 end select
 
+access_ = 'stream'
+
 if (present(iostat)) then
     open(newunit=u, file=filename, &
          action = action_, position = position_, status = status_, &