hg: move unreachable code to where it could be reached

hg

@@ -38,14 +38,8 b" if getattr(sys, 'frozen', None) == 'cons"
             )
         )
 
+try:
 from hgdemandimport import tracing
-
-with tracing.log('hg script'):
-    # enable importing on demand to reduce startup time
-    try:
-        import hgdemandimport
-
-        hgdemandimport.enable()
     except ImportError:
         sys.stderr.write(
             "abort: couldn't find mercurial libraries in [%s]\n"
@@ -54,6 +48,12 b" with tracing.log('hg script'):"
         sys.stderr.write("(check your install and PYTHONPATH)\n")
         sys.exit(-1)
 
+with tracing.log('hg script'):
+    # enable importing on demand to reduce startup time
+    import hgdemandimport
+
+    hgdemandimport.enable()
+
     from mercurial import dispatch
 
     dispatch.run()