fix: scan libraries before install

Author: Luca Bianconi

arduino/libraries/librariesmanager/install.go

@@ -64,6 +64,7 @@ func (lm *LibrariesManager) InstallPrerequisiteCheck(name string, version *semve
 		return nil, err
 	}
 
+	lm.RescanLibraries()
 	libs := lm.FindByReference(&librariesindex.Reference{Name: name}, installLocation)
 
 	if len(libs) > 1 {

arduino/libraries/librariesmanager/librariesmanager.go

@@ -130,8 +130,15 @@ func (lm *LibrariesManager) AddPlatformReleaseLibrariesDir(plaftormRelease *core
 	})
 }
 
+func (lm *LibrariesManager) ClearLibraries() {
+	for k := range lm.Libraries {
+		delete(lm.Libraries, k)
+	}
+}
+
 // RescanLibraries reload all installed libraries in the system.
 func (lm *LibrariesManager) RescanLibraries() []*status.Status {
+	lm.ClearLibraries()
 	statuses := []*status.Status{}
 	for _, dir := range lm.LibrariesDir {
 		if errs := lm.LoadLibrariesFromDir(dir); len(errs) > 0 {