d2-common: Fix blob extraction

Something weird was going on with the formatting of the lib/libril.so
line in proprietary-files.txt, causing setup-makefiles.sh to generate
a flawed copy of d2xxx-vendor-blobs.mk, which in turn causes libril.so
to not be copied into the final output zip when building.

Thanks to elizzle and justin222 for the discovery.

Change-Id: I7921749c3ece34600d036dd95f41b25c1da6f3dd