Added new ENABLE_CODE_COVERAGE option. (#1664)

Modified install.sh script to add this new option

test/common/RcclMockFuncs.hpp

@@ -1,7 +1,11 @@
+#ifndef RCCL_MOCK_FUNCS_HPP
+#define RCCL_MOCK_FUNCS_HPP
+
 #include "info.h"
-#include "comm.h"
 
 void ncclDebugLog(ncclDebugLogLevel, unsigned long, char const*, int, char const*, ...) {};
 ncclResult_t getHostName(char* hostname, int maxlen, const char delim) {
   return ncclSuccess;
 }
+
+#endif  // RCCL_MOCK_FUNCS_HPP