ssl: fix miscellaneous issues found in review. #57

Job	Run time
Build liboqs	1m 20s
Backend double	59s
Backend small-mem	1m 21s
Backend default	1m 4s
Backend avx2	1m 7s
Backend neon (ARM64)	53s
Backend verify-only	1m 9s
Backend avx2+small-mem	1m 1s
Backend asm	1m 6s
Interop (native Falcon vs liboqs Falcon)	1m 16s
	11m 16s

Provide feedback