Move libelf.so.2 from /usr/lib to /lib to unbreak libkvm use after r291406

Tested with the following commands as root:
- yes | make delete-old
- service ldconfig restart
- netstat -nr

X-MFC with: r291406
Reviewed by: jhb, kib
Sponsored by: EMC / Isilon Storage Division

ObsoleteFiles.inc

@@ -38,6 +38,8 @@
 #   xargs -n1 | sort | uniq -d;
 # done
 
+# 20151130: libelf moved from /usr/lib to /lib (libkvm dependency in r291406)
+OLD_FILES+=usr/lib/libelf.so.2
 # 20151115: Fox bad upgrade scheme
 OLD_FILES+=usr/share/locale/zh_CN.GB18030/zh_Hans_CN.GB18030
 OLD_FILES+=usr/share/locale/zh_CN.GB2312/zh_Hans_CN.GB2312

lib/libelf/Makefile

@@ -7,6 +7,7 @@ SRCDIR=	${TOP}/libelf
 .PATH:	${SRCDIR}
 
 LIB=	elf
+SHLIBDIR?= /lib
 
 SRCS=	elf.c							\
 	elf_begin.c						\