Remove LSAN from the debug build

For some unknown reason LSAN catches a SIGSEGV (rdo.c:45) when enabled,
but removing it also removes the supposed SIGSEGV it catches.
To repro, build the earlier build with LSAN, and enter a file that
doesnt exist.
As long as I don't know why LSAN thinks this simple error message causes
a segmentation fault, I will remove it.

Makefile

@@ -1,6 +1,6 @@
 CFLAGS = -Wall -Wextra -Werror -Wl,-z,now
 CFLAGS_RELEASE = ${CFLAGS} -O2 -s -D_FORTIFY_SOURCE=2
-CFLAGS_DEBUG = ${CFLAGS} -O0 -g -fsanitize=leak,undefined
+CFLAGS_DEBUG = ${CFLAGS} -O0 -g -fsanitize=undefined
 LIBS = -lbsd -lcrypt
 CC = gcc