Fix TMT prepare plans

Fix TMT preapre plans to be executed on all distros

Signed-off-by: Tiago Bueno <tbueno@redhat.com>

tests/tmt/plans/main.fmf

@@ -1,14 +1,10 @@
 ---
-adjust:
-    enabled: false
-    when: distro == centos-stream or distro == fedora
 prepare:
   - name: Install ignition package
-    when: use_built_form_src is not defined or use_built_form_src == false
     how: install
     package: ignition
+
   - name: Set IGNITION_BIN_DIR when installed package
-    when: use_built_form_src is not defined or use_built_form_src == false
     how: shell
     script: |
       set -x -e -o pipefail