[core] Use the resolved library path.

GetSharedLibDeps may need to resolve to the absolute path, however, if we give
only the file stem GetSharedLibDeps cannot support features such as resolving
of relative path to $ROOTSYS/lib/. For example,
`cd /home/`; root.exe -e 'gSystem->Load("../test/libEvent.so")'.
`TSystem::Load` will call an interface passing the relative path which will
resolve to $ROOTSYS/lib/../test/libEvent.so, however, if GetSharedLibDeps calls
the same interface it will give the wrong results.

This patch fixes this behavior and optimizes GetSharedLibDeps when we have
already the full path.

core/base/src/TSystem.cxx

@@ -1838,8 +1838,7 @@ int TSystem::Load(const char *module, const char *entry, Bool_t system)
 {
    // don't load libraries that have already been loaded
    TString libs( GetLibraries() );
-   TString moduleBasename( BaseName(module) );
-   TString l(moduleBasename);
+   TString l(BaseName(module));
 
    Ssiz_t idx = l.Last('.');
    if (idx != kNPOS) {
@@ -1887,7 +1886,7 @@ int TSystem::Load(const char *module, const char *entry, Bool_t system)
    int ret = -1;
    if (path) {
       // load any dependent libraries
-      TString deplibs = gInterpreter->GetSharedLibDeps(moduleBasename);
+      TString deplibs = gInterpreter->GetSharedLibDeps(path);
       if (deplibs.IsNull()) {
          TString libmapfilename;
          libmapfilename = path;
@@ -1899,7 +1898,7 @@ int TSystem::Load(const char *module, const char *entry, Bool_t system)
          if (gSystem->GetPathInfo(libmapfilename, 0, (Long_t*)0, 0, 0) == 0) {
             if (gDebug > 0) Info("Load", "loading %s", libmapfilename.Data());
             gInterpreter->LoadLibraryMap(libmapfilename);
-            deplibs = gInterpreter->GetSharedLibDeps(moduleBasename);
+            deplibs = gInterpreter->GetSharedLibDeps(path);
          }
       } else {
          TString delim(" ");