os/FileJournal.cc: fix do-while loop

In case do_submit from libaio fails and returns -EAGAIN the
called continue breaks completely out of the loop since the
loop statement is always false. In this case there is no second
attempt as the code tries. Set the loop condition to true to
fix it.

Fix for:
CID 1297886 (#1 of 1): Structurally dead code (UNREACHABLE)
 continue_in_do_while_false: A continue statement within a do-while
  loop only continues execution of the loop body if the loop
  continuation condition is still true. Since the condition will
  never be true in a "do ... while (false);" loop the continue
  statement has the same effect as a break statement. Did you
  intend execution to continue at the top of the loop?
 do_while_false_condition: This loop will never continue since
  the condition false is never true.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>

src/os/FileJournal.cc

@@ -1451,8 +1451,10 @@ int FileJournal::write_aio_bl(off64_t& pos, bufferlist& bl, uint64_t seq)
 	  continue;
 	}
 	assert(0 == "io_submit got unexpected error");
+      } else {
+	break;
       }
-    } while (false);
+    } while (true);
     pos += aio.len;
   }
   write_finish_cond.Signal();