script: cleanup gcc warnings

script: cleanup gcc warnings

Fix strict gcc warnings that come from using:
  ("-Wall -Wp,-D_FORTIFY_SOURCE=2")

script.c:239: warning: ignoring return value of 'write', declared with attribute warn_unused_result
script.c:330: warning: ignoring return value of 'write', declared with attribute warn_unused_result
script.c:331: warning: ignoring return value of 'fwrite', declared with attribute warn_unused_result

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Karel Zak <kzak@redhat.com>