Explicitly check QFile::open() return value.

backends/merge/Text.cpp

@@ -78,13 +78,13 @@ namespace glabels
 		///
 		void Text::open()
 		{
-			mFile.setFileName( source() );
-			mFile.open( QIODevice::ReadOnly|QIODevice::Text );
-
 			mKeys.clear();
 			mNFieldsMax = 0;
 
-			if ( mLine1HasKeys && mFile.isOpen() )
+			mFile.setFileName( source() );
+			if (mFile.open( QIODevice::ReadOnly|QIODevice::Text ))
+			{
+				if ( mLine1HasKeys )
 				{
 					mKeys = parseLine();
 					if ( (mKeys.size() == 1) && (mKeys[0] == "") )
@@ -97,6 +97,7 @@ namespace glabels
 					}
 				}
 			}
+		}
 
 
 		///