Fix soong scripts to support directories with spaces

Using a path with a space to execute soong is unlikely, but it
might as well work.  Quote all the paths in the soong scripts.

Soong and blueprint will still both fail if the relative path between
the soong script and the source directory has a space in it, but this
is even more unlikely.

Change-Id: I8986f10115209d69b09b82ffea26e4b10d29c197

bootstrap.bash

@@ -27,8 +27,8 @@ fi
 if [[ $# -eq 0 ]]; then
     sed -e "s|@@SrcDir@@|${SRCDIR}|" \
         -e "s|@@PrebuiltOS@@|${PREBUILTOS}|" \
-        ${SRCDIR}/build/soong/soong.bootstrap.in > .soong.bootstrap
-    ln -sf ${SRCDIR}/build/soong/soong.bash soong
+        "${SRCDIR}/build/soong/soong.bootstrap.in" > .soong.bootstrap
+    ln -sf "${SRCDIR}/build/soong/soong.bash" soong
 fi
 
-${SRCDIR}/build/blueprint/bootstrap.bash "$@"
+"${SRCDIR}/build/blueprint/bootstrap.bash" "$@"