Remove a warning. Close ticket #1357.

This commit was SVN r18717.

ompi/mca/btl/tcp/btl_tcp.c

@@ -406,7 +406,7 @@ int mca_btl_tcp_put( mca_btl_base_module_t* btl,
 {
     mca_btl_tcp_module_t* tcp_btl = (mca_btl_tcp_module_t*) btl; 
     mca_btl_tcp_frag_t* frag = (mca_btl_tcp_frag_t*)descriptor; 
-    size_t i;
+    int i;
 
     frag->btl = tcp_btl;
     frag->endpoint = endpoint;
@@ -419,7 +419,7 @@ int mca_btl_tcp_put( mca_btl_base_module_t* btl,
     frag->iov[0].iov_len = sizeof(frag->hdr);
     frag->iov[1].iov_base = (IOVBASE_TYPE*)frag->base.des_dst;
     frag->iov[1].iov_len = frag->base.des_dst_cnt * sizeof(mca_btl_base_segment_t);
-    for(i=0; i<frag->base.des_src_cnt; i++) {
+    for( i = 0; i < (int)frag->base.des_src_cnt; i++ ) {
         frag->hdr.size += frag->segments[i].seg_len;
         frag->iov[i+2].iov_len = frag->segments[i].seg_len;
         frag->iov[i+2].iov_base = (IOVBASE_TYPE*)frag->segments[i].seg_addr.pval;