selftests/android: Fix line continuation in Makefile

selftests/android: Fix line continuation in Makefile

The Makefile lacks a couple of line continuation backslashes
in an `if' clause, which can make the subsequent rsync
command go awry over the whole filesystem (`rsync -a / /`).

  /bin/sh: -c: line 5: syntax error: unexpected end of file
  make[1]: [all] Error 1 (ignored)
  TEST=$DIR"_test.sh"; \
                  if [ -e $DIR/$TEST ]; then
  /bin/sh: -c: line 2: syntax error: unexpected end of file
  make[1]: [all] Error 1 (ignored)
  rsync -a $DIR/$TEST $BUILD_TARGET/;
  [...a myriad of:]
  [  rsync: readlink_stat("...") failed: Permission denied (13)]
  [  skipping non-regular file "..."]
  [  rsync: opendir "..." failed: Permission denied (13)]
  [and many other errors...]
  fi
  make[1]: fi: Command not found
  make[1]: [all] Error 127 (ignored)
  done
  make[1]: done: Command not found
  make[1]: [all] Error 127 (ignored)

Signed-off-by: Daniel Díaz <daniel.diaz@linaro.org>
Acked-by: Pintu Agarwal <pintu.ping@gmail.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>