Fix show_dlopen_error

See the first version of the comment
JuliaPy#592 (comment)

deps/build.jl

@@ -58,9 +58,9 @@ function exec_find_libpython(python::AbstractString, options)
     return readlines(pythonenv(cmd))
 end
 
-function show_dlopen_error(e)
+function show_dlopen_error(lib, e)
     if PYCALL_DEBUG_BUILD
-        println(stderr, "dlopen($libpath_lib) ==> ", e)
+        println(stderr, "dlopen($lib) ==> ", e)
         # Using STDERR since find_libpython.py prints debugging
         # messages to STDERR too.
     end
@@ -75,7 +75,7 @@ function find_libpython(python::AbstractString)
         try
             return (Libdl.dlopen(lib, dlopen_flags), lib)
         catch e
-            show_dlopen_error(e)
+            show_dlopen_error(lib, e)
         end
     end
 
@@ -94,7 +94,7 @@ function find_libpython(python::AbstractString)
             # compare libpython.
             return (libpython, Libdl.dlpath(libpython))
         catch e
-            show_dlopen_error(e)
+            show_dlopen_error(lib, e)
         end
     end