polarssl: set LIB_INSTALL_DIR to baselib

This solves the following warning:

polarssl-1.3.8: polarssl: Files/directories were installed but not shipped
  /usr/lib
  /usr/lib/libpolarssl.so.1.3.8
  /usr/lib/libpolarssl.so.7
  /usr/lib/libpolarssl.so
  /usr/lib/libpolarssl.a
  /usr/lib/.debug
  /usr/lib/.debug/libpolarssl.so.1.3.8 [installed-vs-shipped]
polarssl-1.3.8: polarssl requires libpolarssl.so.7()(64bit), but no providers
in its RDEPENDS [file-rdeps]

Signed-off-by: Chong Lu <Chong.Lu@windriver.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>