Use new function parseint32 in SplitHostPort

Use the new function parseint32 in SplitHostPort instead of calling
strtol directly.

src/netbase.cpp

@@ -47,11 +47,9 @@ void SplitHostPort(std::string in, int &portOut, std::string &hostOut) {
     bool fBracketed = fHaveColon && (in[0]=='[' && in[colon-1]==']'); // if there is a colon, and in[0]=='[', colon is not 0, so in[colon-1] is safe
     bool fMultiColon = fHaveColon && (in.find_last_of(':',colon-1) != in.npos);
     if (fHaveColon && (colon==0 || fBracketed || !fMultiColon)) {
-        char *endp = NULL;
-        int n = strtol(in.c_str() + colon + 1, &endp, 10);
-        if (endp && *endp == 0 && n >= 0) {
+        int32_t n;
+        if (ParseInt32(in.substr(colon + 1), &n) && n > 0 && n < 0x10000) {
             in = in.substr(0, colon);
-            if (n > 0 && n < 0x10000)
             portOut = n;
         }
     }