osbuild-composer.spec: assume no modules in check step

Removes an ineffectual GO111MODULE=off assignment in the build phase, as
we require go to run in module mode at that stage.

In the check phase we run without go modules, so the same stipulation as
on RHEL applies, where the vendor directory gets ignored in certain
cases. Also remove `-mod=vendor` from GOFLAGS on RHEL during the check
phase, as without go modules this is an ineffectual flag.

osbuild-composer.spec

@@ -116,13 +116,6 @@ make man
 # Build test binaries with `go test -c`, so that they can take advantage of
 # golang's testing package. The golang rpm macros don't support building them
 # directly. Thus, do it manually, taking care to also include a build id.
-#
-# On Fedora, also turn off go modules and set the path to the one into which
-# the golang-* packages install source code.
-%if 0%{?fedora}
-export GO111MODULE=off
-export GOPATH=%{gobuilddir}:%{gopath}
-%endif
 
 TEST_LDFLAGS="${LDFLAGS:-} -B 0x$(od -N 20 -An -tx1 -w100 /dev/urandom | tr -d ' ')"
 
@@ -292,14 +285,12 @@ install -m 0644 -vp test/data/rhel-upgrade/*                       %{buildroot}%
 %check
 export GOFLAGS="-buildmode=pie"
 %if 0%{?rhel}
-export GOFLAGS+=" -mod=vendor -tags=exclude_graphdriver_btrfs"
+export GOFLAGS+=" -tags=exclude_graphdriver_btrfs"
+%endif
+
 export GOPATH=$PWD/_build:%{gopath}
 # cd inside GOPATH, otherwise go with GO111MODULE=off ignores vendor directory
 cd $PWD/_build/src/%{goipath}
-%gotest ./...
-%else
-%gocheck
-%endif
 
 %post
 %systemd_post osbuild-composer.service osbuild-composer.socket osbuild-composer-api.socket osbuild-composer-prometheus.socket osbuild-remote-worker.socket