elfedit false "may be used uninitialised"

elfedit.c:904:15: error: 'osabi' may be used uninitialised in this function [-Werror=maybe-uninitialized]
  904 |       osabi = concat (osabi, "|", osabis[i].name, NULL);
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	* elfedit (usage): Avoid false positive "may be used uninitialised".
	Don't leak memory.