dev-install: drop gmerge special casing

Now that build_image installs all the necessary files into the rootfs,
the gmerge package doesn't install anything extra.  That means we no
longer need to hardcode its install.

BUG=chromium:194889
TEST=precq passes
CQ-DEPEND=CL:1492655, CL:1497663

Change-Id: I50c7e874a270e616f7e59971f4d00ccce3c25152
Reviewed-on: https://chromium-review.googlesource.com/1497669
Commit-Ready: ChromeOS CL Exonerator Bot <[email protected]>
Tested-by: Mike Frysinger <[email protected]>
Reviewed-by: Amin Hassani <[email protected]>
1 file changed