build: reorder libraries to address linker error

build: reorder libraries to address linker error

The linker on some systems (for example, Ubuntu 12.04 LTS x86_64)
appears to be sensitive to the order in which libraries are
specified. On these systems, if a library 'A' depends on a library
'B', it has to be specified before 'B' when linking an executable.

  * zebra/Makefile.am: Make sure LIBCAP comes after libzebra.

  * tests/Makefile.am: Ensure libm comes after libbgp.

Signed-off-by: Avneesh Sachdev <avneesh@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>