Following earlier patches, vect_create_epilog_for_reduction contains exactly one 
case where extract_scalar_result==true. Hence, move the code 'if 
(extract_scalar_result)' there, and tidy-up/remove some variables.

bootstrapped on x86_64-none-linux-gnu + check-gcc + check-g++.

gcc/ChangeLog:

	* tree-vect-loop.c (vect_create_epilog_for_reduction): Move code for
	'if (extract_scalar_result)' to the only place that it is true.