Utils: Move result definition to where it's used

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I082c7d500478cab4a2ce29c9d86f2ae2fc99a515
diff --git a/src/Utils.cpp b/src/Utils.cpp
index 308b082..670ac2c 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -301,8 +301,6 @@
 
         number = expression::evaluate(number, exprBegin, exprEnd);
 
-        std::string result = prefix + std::to_string(number);
-
         std::string replaced(find.begin(), find.end());
         while (exprBegin != exprEnd)
         {
@@ -310,6 +308,7 @@
         }
         ret = replaced;
 
+        std::string result = prefix + std::to_string(number);
         while (exprEnd != split.end())
         {
             result.append(" ").append(*exprEnd++);