Detect and report missing boost-test lines in input log file

[SVN r39647]

tools/regression/process_jam_log.cpp

@@ -681,6 +681,14 @@ int cpp_main( int argc, char ** argv )
            line_start.find( ".linkonce" ) == string::npos )
     )
     {
+      if ( !test2info.size() )
+      {
+        std::cout << "*****Error - No \"boost-test\" lines encountered.\n"
+                     "     (Usually occurs when bjam was envoked without the --dump-tests option\n"
+                     "      or bjam was envoked in the wrong directory)\n";
+        return 1;
+      }
+
       string action( ( line_start.find( "Link-action" ) != string::npos
             || line_start.find( "vc-Link" ) != string::npos 
             || line_start.find( "Archive-action" ) != string::npos