cmake-gui: Align source and binary directory path text

Text inputs for "where is the source code" and "where to build the
binaries" had different amount of left spacing, so the two paths were
not aligned. This could create a feeling that you typed something wrong
in the input even though the paths were identical or had a common root
path.

Source/QtDialog/CMakeSetupDialog.ui

@@ -57,6 +57,9 @@
          <verstretch>0</verstretch>
         </sizepolicy>
        </property>
+       <property name="styleSheet">
+        <string notr="true">padding-left: 0</string>
+       </property>
        <property name="editable">
         <bool>true</bool>
        </property>