ostree-sysroot-deploy.c: delete redundant check

Just noticed this while inspecting the code. The deployments retrieved
by `_ostree_sysroot_list_deployment_dirs_for_os` will forcibly already
have a matching osname since it indirectly uses that same variable to
construct them. Having a check there makes it look like there may be
subtle corner cases, when there aren't.

Closes: #529
Approved by: cgwalters

src/libostree/ostree-sysroot-deploy.c

@@ -2011,8 +2011,6 @@ allocate_deployserial (OstreeSysroot           *self,
     {
       OstreeDeployment *deployment = tmp_current_deployments->pdata[i];
 
-      if (strcmp (ostree_deployment_get_osname (deployment), osname) != 0)
-        continue;
       if (strcmp (ostree_deployment_get_csum (deployment), revision) != 0)
         continue;