fix crash on ALSA SW fallback

stepmania/src/arch/Sound/ALSA9Dynamic.cpp

@@ -43,15 +43,14 @@ CString LoadALSA()
 	return "";
 error:
 	UnloadALSA();
-	if( Handle )
-		dlclose( Handle );
-	Handle = NULL;
 	return error;
 }
 
 void UnloadALSA()
 {
-	dlclose( Handle );
+	if( Handle )
+		dlclose( Handle );
+	Handle = NULL;
 #define FUNC(ret, name, proto) d##name = NULL;
 #include "ALSA9Functions.h"
 #undef FUNC

stepmania/src/arch/Sound/RageSoundDriver_ALSA9.cpp

@@ -214,7 +214,7 @@ RageSound_ALSA9::RageSound_ALSA9()
 	CString err = LoadALSA();
 	if( err != "" )
 		RageException::ThrowNonfatal("Driver unusable: %s", err.c_str());
-
+try {
 	shutdown = false;
 
 	/* Create a bunch of streams and put them into the stream pool. */
@@ -249,6 +249,10 @@ RageSound_ALSA9::RageSound_ALSA9()
 
 	MixingThread.SetName( "RageSound_ALSA9" );
 	MixingThread.Create( MixerThread_start, this );
+} catch(...) {
+	UnloadALSA();
+	throw;
+}
 }
 
 RageSound_ALSA9::~RageSound_ALSA9()

stepmania/src/arch/Sound/RageSoundDriver_ALSA9_Software.cpp

@@ -183,7 +183,7 @@ RageSound_ALSA9_Software::RageSound_ALSA9_Software()
 	CString err = LoadALSA();
 	if( err != "" )
 		RageException::ThrowNonfatal("Driver unusable: %s", err.c_str());
-
+try {
 	shutdown = false;
 
 	max_writeahead = safe_writeahead;
@@ -198,6 +198,11 @@ RageSound_ALSA9_Software::RageSound_ALSA9_Software()
 	
 	MixingThread.SetName( "RageSound_ALSA9_Software" );
 	MixingThread.Create( MixerThread_start, this );
+} catch(...) {
+	UnloadALSA();
+	throw;
+}
+
 }
 
 RageSound_ALSA9_Software::~RageSound_ALSA9_Software()