set flashmap install prefix to /usr instead of /usr/local

/usr/local/ does not exist on non-developer images in Chrome OS.

BUG=chromium-os:22304
TEST=Built locally and ensured files are placed in /usr instead of /usr/local.

For x86-generic:
/build/x86-generic/usr/lib/libfmap.so
/build/x86-generic/usr/lib/libfmap.so.0
/build/x86-generic/usr/lib/pkgconfig/fmap.pc
/build/x86-generic/usr/lib/libfmap.so.0.0.0
/build/x86-generic/usr/include/fmap.h
/build/x86-generic/usr/sbin/fmap_encode
/build/x86-generic/usr/sbin/fmap_decode
/build/x86-generic/usr/sbin/fmap_csum

For amd64-generic:
/build/amd64-generic/usr/lib/pkgconfig/fmap.pc
/build/amd64-generic/usr/lib64/libfmap.so
/build/amd64-generic/usr/lib64/libfmap.so.0
/build/amd64-generic/usr/lib64/libfmap.so.0.0.0
/build/amd64-generic/usr/include/fmap.h
/build/amd64-generic/usr/sbin/fmap_encode
/build/amd64-generic/usr/sbin/fmap_decode
/build/amd64-generic/usr/sbin/fmap_csum

Change-Id: I64278c91c4b52f4d89d8d174a579ddb62da3a0c1
1 file changed