Fix after security review

Fix after security review

* File: src/shared/util.c
  Function: write_fd
  Write in function may return EINTR correctly. Function does  not
  support this case correctly. If the interrupt occurs program will not
  dump all data to file. The interrupt may come from child process
  (SIGCHILD).

* File: src/shared/util.c
  Function: fprintf_fd
  You may replace fprintf_fd with standard library function dprintf.

* File: src/shared/util.c
  Functions: dump_file_write_fd, copy_file, cat_file
  Functions don’t support EINTR correctly (write in function write_fd
  may be interrupt). In this functions it is not clear who will generate
  signal to interrupt write call, so this is not security risk now.  You
  may replace loop with standard library function sendfile.

* File: crash-manager.c
  Function: launch_crash_popup
  Memory leak: value conn was allocated but was not deallocated.

* File: crash-manager.c
  Function: prepare_paths
  Invalid strings are stored in crash_crash_path and crash_temp_path.
  Both strings are truncated by 1 byte.

Change-Id: Ie174b5ee043321861912f1b9233f0f6a6afd027e