Take fileNames by value in InputFileCatalog constructor

The constructor makes a copy of the fileNames anyway. For the cases
where InputFileCatalog is constructed with temporary or moved
vector<string>, this change allows to avoid copying that vector.

The Sources tend to pass in directly a temporary vector<string> from
the ParameterSet, so there could be a visible reduction in memory
churn.

FWCore/Catalog/interface/InputFileCatalog.h

@@ -33,7 +33,7 @@ namespace edm {
 
   class InputFileCatalog {
   public:
-    InputFileCatalog(std::vector<std::string> const& fileNames,
+    InputFileCatalog(std::vector<std::string> fileNames,
                      std::string const& override,
                      bool useLFNasPFNifLFNnotFound = false,
                      //switching between two catalog types

FWCore/Catalog/src/InputFileCatalog.cc

@@ -17,12 +17,12 @@
 
 namespace edm {
 
-  InputFileCatalog::InputFileCatalog(std::vector<std::string> const& fileNames,
+  InputFileCatalog::InputFileCatalog(std::vector<std::string> fileNames,
                                      std::string const& override,
                                      bool useLFNasPFNifLFNnotFound,
                                      edm::CatalogType catType)
       : fileCatalogItems_(), overrideFileLocator_() {
-    init(fileNames, override, useLFNasPFNifLFNnotFound, catType);
+    init(std::move(fileNames), override, useLFNasPFNifLFNnotFound, catType);
   }
 
   InputFileCatalog::~InputFileCatalog() {}