koji: Rewrite available test using for-else statements

This saves an extra variable but could make it harder to read.

https://docs.python.org/3/tutorial/controlflow.html#else-clauses-on-loops

Co-authored-by: Yann Dirson <yann.dirson@vates.tech>
Signed-off-by: Philippe Coval <rzr@users.sf.net>

Author: rzr

scripts/koji/koji_build.py

@@ -53,17 +53,17 @@ def check_commit_is_available_remotely(dirpath, hash, target, warn):
         if target is not None and re.match(r'v\d+\.\d+-u-.+', target):
             raise Exception("Building with a user target requires using --pre-build or --test-build.\n")
         try:
-            available = False
             supported_branches = PROTECTED_TARGETS.get(target)
             if supported_branches:
                 for branch in supported_branches:
-                    available = is_remote_branch_commit(dirpath, hash, branch)
-                    if available:
+                    if is_remote_branch_commit(dirpath, hash, branch):
                         logging.debug(f"commit {hash} is on top of branch {branch} (target: {target})")
                         break
-            if not available:
-                raise Exception(f"The current commit is not the last commit of any remote branches {supported_branches}.\n"
-                            f"This is required when using the protected target {target}.\n")
+                else:
+                    raise Exception(f"The current commit is not the last commit of any remote branches {supported_branches}.\n"
+                                f"This is required when using the protected target {target}.")
+            else:
+                raise Exception(f"Protected target {target} has no allowed branches.")
         except Exception as e:
             if warn:
                 print(f"warning: {e}", flush=True)