dev-install: fix target of local make.profile

We need to point to the make.profile, not the entire portage config.

BUG=chromium:194889
TEST=precq passes & created profile works w/emerge

Change-Id: I3af3dbbaceecf8c17747d1f536d58783baea7970
(cherry picked from commit a02cc337a6cc9d11f9c4d1cc34e17e637a57f48f)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/1518289
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/dev-install/dev_install b/dev-install/dev_install
index 21a6e41..f5bdca3 100755
--- a/dev-install/dev_install
+++ b/dev-install/dev_install
@@ -138,7 +138,8 @@
   # Copy emerge configuration to /usr/local.
   mkdir -p -m 0755 "${P_CONFIG_DEVELOPER}/make.profile"
   # Point our local profile to the rootfs one.  This allows us to stack.
-  echo "${P_CONFIG_CROS}" > "${P_CONFIG_DEVELOPER}/make.profile/parent"
+  echo "${P_CONFIG_CROS}/make.profile" \
+    >"${P_CONFIG_DEVELOPER}/make.profile/parent"
 
   # Install the package.provided entries for the rootfs.
   mkdir -p -m 0755 "${P_CONFIG_DEVELOPER}/make.profile/package.provided"