Build everything if the buildOnly param is not set

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>

Jenkinsfile

@@ -118,26 +118,26 @@ properties([
     ])
 ])
 
-def buildCandidates = [:]
-
 def buildOnlyList = params?.buildOnly.tokenize(/, ?/).collect { it.tokenize('/') }
-
 buildOnlyList = buildOnlyList
   .groupBy{ it[0] }
   .collectEntries{ arch, values -> [arch, values.findResults { it[1] } ] }
 
-buildCandidates = architectures
-  // filter out architectures which won't be built
-  .subMap(buildOnlyList.keySet())
-  .collectEntries{ arch, architecture ->
-    // filter out artifact types which won't be built
-    types = architecture.types
-    if (buildOnlyList[arch])
-        types = architecture.types.subMap(buildOnlyList[arch])
-    [arch, architecture + [
-      types: types
-    ]]
-  }
+def buildCandidates = architectures
+if (buildOnlyList) {
+    buildCandidates = buildCandidates
+      // filter out architectures which won't be built
+      .subMap(buildOnlyList.keySet())
+      .collectEntries{ arch, architecture ->
+        // filter out artifact types which won't be built
+        types = architecture.types
+        if (buildOnlyList[arch])
+            types = architecture.types.subMap(buildOnlyList[arch])
+        [arch, architecture + [
+          types: types
+        ]]
+      }
+}
 
 // SSH complains loudly if the current user is not in the user database, so fake that
 def withSshAgent(credentials, command) {